Search PubMed⌕ Search

Biomedical subjects

T Bauer

Publications and source records attributed to T Bauer.

At least 109 records · Page 6Linked to original sources
PubMed1994

Hypoxic stimulation of vascular endothelial growth factor expression in vitro and in vivo.

BACKGROUND: Vascular endothelial growth factor (VEGF) is a specific endothelial cell mitogen with potent angiogenic properties. In tumors, VEGF has been localized to the most necrotic and ischemic areas of the tissues, suggesting that local hypoxia is a potent inducer of VEGF production. Initial experiments in vitro confirmed the stimulatory effect of hypoxia on VEGF expression. The extent of this response and the mechanisms involved in oxygen sensing are poorly characterized. EXPERIMENTAL DESIGN: Confluent monolayers of malignant cell lines or primary cultures of fibroblast or endothelial cells were exposed to hypoxia or incubated with either cobalt chloride, a stimulator of erythropoietin gene expression, or sodium azide, an inhibitor of oxydative phosphorylation. VEGF expression was analyzed by Northern blot or RNase protection assays. The expression VEGF in vivo was studied in animals subjected to hypobaric hypoxia or functional anemia. RESULTS: Hypoxia greatly stimulated VEGF expression in tumor cell lines and primary fibroblast cultures. Endothelial cells, that expressed very low constitutive levels of VEGF, were resistant to hypoxic stimulation. RNase protection analysis showed that hypoxia primarily stimulated the induction of smaller and medium VEGF isoforms, i.e., the same ones expressed under normal conditions. The stimulatory effect of hypoxia on VEGF could be reproduced in vitro by cobalt chloride but not with sodium azide. In vivo, both hypoxia and anemia were found to be potent inducers of VEGF expression in several organs including heart, brain, liver, kidney, and muscle. As in vitro, cobalt was also found to be a potent stimulator of VEGF in vivo. CONCLUSIONS: Hypoxia is a potent inducer of VEGF expression in malignant as well as normal cultured cells. It is also a stimulator of VEGF expression in vivo. The VEGF gene appears to respond to hypoxia like the erythropoietin gene, and the mechanism of oxygen sensing probably is mediated by a heme-containing protein.

Anemia↗
PubMed1994

[Xenogenic cartilage as a transplant for reconstruction of the facial skull].

90 patients were followed-up, in whom 110 cartilage grafts of bovine origin (Chondroplast) had been inserted. Nose and orbit (46 and/or 32 cartilage grafts) were the most frequent implantation sites. In three out of those 90 patients incorporation of the grafts was eventful. In two out of those three complication finally resulted in a loss of the graft. When following-up in 57 patients whether the grafts had kept their shape we found out that the cartilage grafts had still kept their shape quite well after three and a half years in 50 patients.

Animals↗
PubMed1993

137Cs transfer after Chernobyl from fodder into chicken meat and eggs.

The distribution and the biological half-lives of 137Cs in poultry after continuous intake of foodstuffs contaminated by the Chernobyl fallout were studied in order to determine transfer coefficients to yolk, albumen, and shell of eggs as well as transfer coefficients to chicken meat. Mean values for laying hens were found to be 0.2 d kg-1 (whole consumable egg), 1.2 d kg-1 (leg meat), and 1.6 d kg-1 (breast meat) when radiocesium was fed in contaminated grass pellets, and about twice as large [i.e., 0.4 d kg-1 (whole consumable egg), 2.8 d kg-1 (leg meat), and 3.0 d kg-1 (breast meat)] when radiocesium was fed in contaminated wheat. Reducing effects of the feed additive ammonium-ferric-cyano-ferrate in concentrations of 0.66 g kg-1 of feed mixture on the contamination of hen products were quantified to be a factor of 3 to 4 (whole consumable egg and meat after grass pellet feeding) and 8 to 14 (whole consumable egg and meat after wheat feeding). A drastically higher reduction with an ammonium-ferric-cyano-ferrate dose twice as large (1.33 g kg-1) was achieved. For broiler chickens, activity concentration ratios of meat to feed were derived for various fattening periods, with mean values of about 0.3 (leg), 0.4 (breast), and 0.2 (liver). The addition of ammonium-ferric-cyano-ferrate reduced the activity concentrations in meat by factors of more than 6.

Accidents↗
PubMed1993

Hemorrhagic transformation in cardioembolic cerebral infarction.

BACKGROUND AND PURPOSE: Because the frequency of hemorrhagic transformation of cerebral infarcts is still a matter of controversy, we performed a prospective magnetic resonance imaging study in a series of consecutive patients with cardioembolic stroke. SUMMARY OF REVIEW: Among 200 consecutive patients with transient ischemic attack or ischemic stroke, 41 were identified with a computed tomographically proven supratentorial infarct due to cardiogenic embolism. Magnetic resonance imaging (T1-weighted) was performed 3 weeks after the stroke in 35 of these 41 patients. Eight patients received anticoagulants. Magnetic resonance images showed hemorrhagic transformation in 68.6% (24) of the 35 infarcts, always without clinical deterioration. In a stepwise forward logistic regression analysis only the volume of infarction edema on the initial computed tomogram was linked significantly with the risk of hemorrhagic transformation (p = 0.037). Hemorrhages were a regular finding on magnetic resonance images of infarcts exceeding a volume of 10 cm3 (94.4%, 17 of 18). CONCLUSIONS: Hemorrhagic transformation is a regular finding in medium-sized and large cardioembolic infarcts. Thus, in therapeutic and preventive studies of acute stroke the severity, not the frequency, of hemorrhages into brain infarcts should be the matter of interest.

Adult↗
PubMed1992

[Lesion of the brachial plexus caused by traumatic aneurysma spurium of the axillary artery--case report of two patients].

The indirect lesion of the brachial plexus by a traumatic false aneurysm of the axillary artery is a rare event. Clinical signs, diagnosis and follow-up of two patients are reported. Characteristic symptoms are persistent shoulder pain and progredient neurologic deficits with delayed onset. Examination for a jet phenomenon in the axillary region may confirm the suspected diagnosis. Colour duplex-sonography and magnetic resonance tomography are the most valid non-invasive radiological methods beside computerised tomography. Surgical treatment with resection of the aneurysm is recommended as soon as possible.

Aneurysm, False↗
PubMed1992

Imaging of the intracranial vertebrobasilar system using color-coded ultrasound.

BACKGROUND: Anatomic variety and difficult accessibility of the vertebrobasilar arteries pose considerable problems to conventional ultrasound. We evaluated the diagnostic potential of transcranial color-coded sonography in the distal part of this system. METHODS: We insonated the intracranial section of the vertebrobasilar arteries through the foramen magnum window in 24 healthy individuals using a Doppler color flow imaging system in connection with a 2.5-MHz sector transducer. Magnetic resonance images in special inclination planes were performed and compared with the color-coded duplex images in five cases. RESULTS: The B-mode image of the craniocervical junction and the intracranial parenchymal structures in addition to the color-coded blood flow allowed an unambiguous identification of the vertebrobasilar arteries (vertebral artery, 96%; basilar artery, 79%; and posterior inferior cerebellar artery, 50%). Blood flow velocities were measured considering the insonation angles: vertebral arteries, 50/24 cm/sec (30 degrees); basilar artery, 59/28 cm/sec (4 degrees); and posterior inferior cerebellar artery, 56/30 cm/sec (20 degrees) [peak systolic/end diastolic blood flow velocity (mean angle correction)]. CONCLUSIONS: Transcranial color-coded sonography enables accurate identification and differentiation of the intracranial vertebrobasilar arteries and improves accuracy of Doppler measurements. It may prove useful for evaluation of tortuosity and for hemodynamic studies in this vascular territory.

Adolescent↗
PubMed1992

Thermal and pH stability of pestiviruses.

Three strains/isolates of hog cholera virus (HCV) and two strains/isolates each of cytopathogenic (cp) and non-cytopathogenic (ncp) biotype of bovine virus diarrhoea virus (BVDV) were each exposed to pH 3, 3.5 and 4 at 4 degrees C, 21 degrees C and 37 degrees C in a number of combinations. Infectivity titration and half-life determinations following correlation and regression analysis showed a significant temperature-dependent shortening of half-lives within the pH range investigated. At pH 3, mean half-lives were more than tenfold lower when HCV was kept at an ambient temperature of 21 degrees C rather than at 4 degrees C. Additionally, in some of the strains/isolates tested, half-lives of HCV kept at 4 degrees C were four to ten times lower when the pH was raised from 3 to 4. BVDV appeared more sensitive at 4 degrees C and pH 3 than HCV, but equally sensitive at 21 degrees C. Differences in temperature or pH stability between cp and ncp biotypes of BVDV could not be statistically verified although, in general, the cp biotypes seemed to be more stable than the ncp strains/isolates.

Animals↗
PubMed1992

Surgery, dopamine agonist therapy of combined treatment--results in prolactinoma patients after a 12 month follow-up.

In a non-randomized retrospective study n = 36 prolactinoma patients (n = 7 micro- and n = 29 macroadenomas) were evaluated before (E0), 4 (E1) and 52 weeks (E2) after applying 3 different treatment modalities: A dopamine agonist (DA) therapy (n = 14), B surgery as initial procedure (n = 12) and oral DA therapy, C DA preinjection, subsequent surgery (n = 10) and oral DA medication. T0 outline the effect of the 3 regimens upon serum prolactin (PRL) and tumour size reduction, clinical signs and symptoms, anterior/posterior pituitary lobe function and MRI/CT findings were evaluated in each patient at E0, E1 and E2. In group A, PRL normalization was achieved in n = 10 patients (71%), although the frequency of an empty sella was only one out of 12 macroprolactinoma patients (less than 10%). Patients of group C showed the lowest PRLE2 levels (32 +/- 11 ng/ml, normalization rate 60%), although not statistically significant when compared with the other groups (A: 41 +/- 28 ng/ml, B: 114 +/- 33 ng/ml, normalization rate 31%). According to MRI studies in groups B and C total removal was achieved in 33% and 50% of macroprolactinomas, respectively. The most favourable ratio of the leading pre/posttreatment signs and symptoms was observed in patients of group C. It was concluded that no superiority of either treatment regimen exists for prolactinoma patients. Each mode of therapy has its own benefits which may be applied to the different biological behaviour of a prolactinoma in the respective patient.

Adolescent↗
PubMed1991

Mass spectrometric and high-performance liquid chromatographic studies of medroxyprogesterone acetate metabolites in human plasma.

Medroxyprogesterone acetate (MPA) treatment has been shown to exert several beneficial effects in cancer patients. It has been suggested that such effects are due in part to the metabolites derived from MPA in vivo. The first results are reported on the identification of 2 alpha-hydroxy- and 21-hydroxy-MPA, 20-dihydro-MPA, 17 alpha-acetoxy-2 alpha,3 beta-dihydroxy-6 alpha-methylpregn-1,4-dien-20-one and two X,21-dihydroxy-MPAs, one of them presumably being 6 alpha-hydroxymethyl-21-hydroxy-MPA, in patient's plasma by high-performance liquid chromatographic (HPLC), gas chromatographic-mass spectrometric and NMR methods. Additionally, the presence of other metabolites such as di- and tetrahydro-MPAs and 6,21-dihydroxy-MPA, found in urine and other samples, was demonstrated in plasma. For routine clinical examinations an HPLC method is described for determination of, e.g., the unreduced MPA metabolite group in Sep-Pak-ODS column extracts of patients' plasma.

Chromatography, High Pressure Liquid↗
PubMed1990

[Osteoid osteoma at the end of the phalanx of the big toe].

A 20-year-old man with persistent pain in the left big toe associated with broadening, thickening and discolouration of the toenail had been treated unsuccessfully for 21 months by surgical measures (wedge excision, avulsion of the nail) and local applications (antibiotics, antimycotics, disinfectants). A radiograph of the left big toe showed an area of calcification 0.5 cm in diameter at the base of the terminal phalanx. It was surrounded by a narrow zone of transradiancy and projected upwards above the margin of the bone. Among the diagnostic possibilities were osteomyelitis and osteoid osteoma. Biopsy revealed the latter, and the patient was cured by "en bloc" resection of the tumour. This case shows that abnormalities of nail growth of the kind commonly associated with paronychia may occasionally be due to a neoplastic lesion in the terminal phalanx.

Adult↗
PubMed1990

[Factors determining the development of wound infection after appendectomy].

In order to illustrate which factors are of significance for the development of wound infection after appendectomy, an extensive prospective material of 2,097 patients submitted to appendectomy was analysed. Regression analyses demonstrated that age alone, employment of preoperative antibiotics (cefoxitin) and patient delay (time from onset of symptoms till admission) were of significance. The present authors conclude, on the basis of this material, that all patients over 25 years of age should be given preoperative antibiotic prophylaxis which covers aerobic and also anaerobic microorganisms. If a gangrenous or perforated appendix is found, antibiotics should be administered intraoperatively if prophylactic treatment has not been administered. In cases of perforation, antibiotics should be administered postoperatively for 72 hours.

Adolescent↗
PubMed1990

[Differential diagnosis of acral blood circulation disorders using intra-arterial DSA of the hand].

32 patients with secondary Raynaud's syndrome and known basic disease (thromboangiitis obliterans, arterial sclerosis, collagenosis) were examined by high-resolution arterial subtraction angiography. There were typical organic fixed vessel irregularities in relation to the extent of the disease. In early stages, however, the functional vasospastic disorder dominates. The extent and the reversibility of the vasospasm were documented after pharmacological treatment. Pharmacoangiography of the hand can therefore be used as helpful method in the differential diagnosis and therapy of Raynaud's syndrome.

Adult↗
PubMed1990

Voiding patterns in men evaluated by a questionnaire survey.

A questionnaire on obstructive and irritative voiding symptoms was sent to 572 men aged between 20 and 79 years, selected at random from the National Register; 337 questionnaires were completed. None of the responders had consulted a doctor because of voiding symptoms. There was a significant increase in voiding symptoms and in the obstructive, irritative and total symptom scores between the sixth and seventh [corrected] decades, whereas the increases in the other decades were small. Only the prevalence of terminal dribbling was uniform. The prevalence of single obstructive and irritative voiding symptoms in men aged 60 to 79 years without subjective prostatism was the same as in patients admitted with prostatism, although most of the men had milder symptoms. Only nocturia and urge incontinence were more prevalent in patients admitted with prostatism. About 20% of men in the oldest decades had symptoms equal in severity to those found in men undergoing prostatectomy; 29% and 11% of men in the eighth decade [corrected] had nocturia twice and 3 times or more respectively; 19% complained of urge incontinence. More information on possible treatment is needed.

Adult↗
PubMed1990

Voiding patterns and prevalence of incontinence in women. A questionnaire survey.

A detailed questionnaire on the occurrence of irritative and obstructive voiding symptoms, incontinence and the number of childbirths was sent out to 600 women aged between 20 and 79 years, randomly selected from the National Register; 432 (72%) returned the questionnaire and 414 (69%) were evaluable. The frequency of obstructive symptoms such as hesitancy, intermittency and decreased stream was low. Diurnal frequency with voiding intervals less than 3 h were recorded by more than 50% of the women and about 10% voided more frequently than every second hour. Nocturia increased significantly with age; 54 (13.6%) voided at least twice per night. About 40% complained of incontinence but this was troublesome in only 6%; 15.3, 13.3 and 11.5% had stress, urge and mixed incontinence respectively. More than 8% wore nappies or sanitary towels every day to protect against urinary leakage. Although the tendency to wear nappies or sanitary towels increased with age, the increase was not statistically significant. There was a positive correlation between the occurrence of stress incontinence and childbirth in the group as a whole.

Adult↗
PubMed1989

Determination of the transfer of cesium and iodine from feed into domestic animals.

The transfer of 131I and 137Cs, released after the Chernobyl accident, into domestic animals was studied experimentally in order to determine transfer coefficients from feed into animal products under realistic conditions. The 137Cs transfer coefficients for meat were calculated to be: 0.01 d/kg beef (cow), 0.038 d/kg beef (heifer), 0.038 d/kg beef (bull), 0.35 d/kg veal, 0.4 d/kg pork, 0.33 d/kg sheep, 0.28 d/kg fallow deer and 1.3 d/kg chicken. The transfer coefficients for cow's milk were calculated to be 0.007 d/1 (131I) and 0.003 d/1 (137Cs), and for sheep's milk 0.06 d/1 (137Cs). In egg-white and yolk transfer coefficients for 137Cs of 0.2 and 0.1 d/kg, respectively, could be determined. Biological half-lives and the influence of feed additives on the activity concentrations in meat and animal products are described.

Accidents↗
PubMed1989

Antibiotic prophylaxis in acute nonperforated appendicitis. The Danish Multicenter Study Group III.

In a prospective, block-randomized, multicenter study, the safety and efficacy of cefoxitin in preoperative prophylaxis were studied. 1735 patients undergoing appendectomy were evaluable, and half of these patients received 2 g of cefoxitin before undergoing operation. The patients were divided into three groups: patients with a normal appendix, patients with an acutely inflamed appendix, and patients with a gangrenous appendix. The study showed for each group a significant reduction of the incidence of wound infection in patients receiving prophylaxis. However, intra-abdominal abscess formation was not influenced by preoperative antibiotic prophylaxis. Consequently, routine preoperative prophylaxis is recommended before appendectomy.

Abdomen↗