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Biomedical subjects

W Müller

Publications and source records attributed to W Müller.

At least 505 records · Page 28Linked to original sources
PubMed1990

Retroviral interleukin 4 gene transfer into an interleukin 4-dependent cell line results in autocrine growth but not in tumorigenicity.

A retroviral vector has been constructed containing the mouse interleukin 4 (IL 4) gene under the transcriptional control of the thymidine kinase promoter. Infection of the IL 4-dependent T cell line CT4S by the thymidine kinase IL 4 construct resulted in factor-independent growth. The infected cells grow as a consequence of continuous consumption of the endogenously produced IL 4. Clones were established secreting different amounts of IL 4 but none of them was capable of growing in vivo. The lack of correlation between factor-independent growth and tumorigenicity distinguishes IL 4 from other growth factors and could reflect the recently reported activity of IL 4 to suppress tumor growth in vivo.

Animals↗
PubMed1990

Mitotic disturbance associated with mosaic aneuploidies.

The association of various unsystematic aneuploidies with premature centromere division (PCD) was observed in a patient with conspicuous clinical features and combined immunodeficiency. Trisomies and monosomies of almost all autosomes and gonosomal aberrations were found separately or in combination in a majority of the proband's lymphocytes and fibroblasts. The chromosome number varied from 44 to 50. A high proportion of the metaphases showed PCD or had the appearance of C-anaphases. These findings probably represent a new mutant affecting mitosis and causing mosaic aneuploidies.

Aneuploidy↗
PubMed1990

Significance of eosinophilic granulocytes in chronic subdural hematomas.

Despite a number of studies on infiltration of eosinophilic granulocytes into the outer membrane of chronic subdural hematomas, the significance of this phenomenon is not clear. We investigated histologically the membranes of 40 patients with chronic subdural encapsulated hematoma. Infiltrations with eosinophilic leucocytes were found in the granulation tissue of the inner layer of the outer membrane, either diffuse and sporadic (12 cases) or as massive agglomerations (28 cases). Fifty percent of the patients with marked infiltrations were between 61 and 80 years old. In 5 cases Charcot-Leyden crystals were identified. The numerous functions of the eosinophils play a more important role in repair than in maintenance of fluidity of hematomas.

Aged↗
PubMed1990

Clinical correlates of erythropoiesis in chronic subdural hematoma.

Histologic investigation was performed in 38 out of 224 chronic subdural hematomas treated at our institution from 1978 to 1988. Nucleated red blood cells were found in 33% of the chronic subdural membranes examined. Additional sections were examined in 14 of these 38 patients, revealing erythroblasts in 57%. The clinical course and radiographic findings in the patients whose membranes contained erythroblasts were compared with those whose specimens did not. Neither history, presentation, size of hematoma, nor postoperative recovery differed from one group to the other. By comparing histologic and clinical findings, we are able to conclude that the production of erythrocytes by chronic subdural membranes is of no surgical significance.

Adult↗
PubMed1990

Absence of genotoxic activity of penbutolol in bacterial and mammalian cell screening systems.

The genotoxic potential of the beta-adrenergic blocker penbutolol was assessed using the Ames and HGPRT tests, unscheduled DNA synthesis (UDS) and alkaline elution assays. In the Ames test, penbutolol was tested for cytotoxicity and genotoxic activity in concentration ranges of 0.8-500 micrograms/plate and 0.1-125 micrograms/ml in the HGPRT, UDS and alkaline elution assays. In the Ames test penbutolol showed significant toxicity above 500 micrograms/plate. In the mammalian cells (V79) used for the HGPRT test and A459 cells used for alkaline elution and UDS assays, penbutolol was cytotoxic at concentrations above 30 micrograms/ml. In another series of experiments, male Wistar rats were treated i.p. with penbutolol (1, 10 and 100 mg/kg) and after 2 h liver nuclei were isolated and formation of single DNA-strand breaks was measured. The results of the present study demonstrate the absence of genotoxic activity of penbutolol in the 5 strains of Salmonella typhimurium (TA98, TA100, TA1535, TA1537 and TA1538) and in the strain of Escherichia coli WP2 uvrA in the presence or absence of metabolic activation. In V79 cells, penbutolol showed no mutagenic effects at the HGPRT locus in the presence or absence of metabolic activation. Additionally, no significant incorporation of [3H]thymidine into the DNA in the UDS test or formation of DNA-strand breaks in the alkaline elution assay was detected in the non-toxic concentration range of penbutolol with or without metabolic activation. Furthermore, penbutolol did not cause DNA damage in liver nuclei isolated from penbutolol-treated rats.

Animals↗
PubMed1990

Perioperative assessment of cardiac energy metabolism by means of arterio-coronary venous difference in lactate concentration (acDL). A parameter for optimizing ventricular function of the postcardioplegic myocardium.

Fourty-three patients undergoing open heart surgery were subjected to extended hemodynamic and metabolic monitoring (arterial and coronary sinus (CS) lactate concentration). In 95% of patients investigated, a significant increase in CS lactate concentration above the arterial lactate concentration was established at the beginning of reperfusion (RPT). In these cases, a decrease in the CS lactate below the arterial concentration occurs within the RPT creating a cross-over point (COP) from negative to positive lactate extraction values. Whereas the initial rise in CS lactate is an expression of the expected ischemia-induced acceleration of anaerobic glycolysis, the onset of a positive lactate extraction can be related to reconsolidation of mitrochondrial oxidative phosphorylation. We found two groups with an early and late COP at 7.2 +/- 0.8 min (ECOP) and 42.5 +/- 5.2 min (LCOP) (P less than 0.005). Whereas a short cross-over time was associated with a normal postoperative outcome, cardiac recovery was delayed in the LCOP group. With the aid of metabolic monitoring it is possible to identify the COP and cardiac overload situations and so to optimize the perioperative outcome, especially in selected patients (NYHA stage III/IV, re-operation, high-risk operation).

Adenosine Triphosphate↗
PubMed1990

Photodynamic therapy in head and neck surgery.

The results of a clinical study of photodynamic therapy (PDT) on early stage cancer in head and neck surgery are presented in this report. 30 patients with T1 malignancies of the face and oropharynx have been treated primarily with PDT. After the longest follow up of 14 months two patients revealed recurrence of the disease or residual tumor, two patients have been retreated because of residual dysplastic cells in the control biopsy, and all other patients stay histologically proven free of disease. Hence, PDT appears to be a promising cancer treatment for different histological tumors that penetrate the host tissue definitely less than a laser beam of 630 nm, which is the appropriate wavelength for PDT. Deeper-penetrating malignomas may be accessable for PDT using insertable filters when applying interstitial laser light.

Basal Cell Carcinoma↗
PubMed1990

[Ultrasound instruments for surgical purposes--technical aspects and selected areas for use].

Surgical instruments simulated to oscillate by means of low-frequency performance ultrasound are particularly useful for specific fields of application. A survey describes the technical principle of action and the development work carried out at the Technical University of Karl-Marx-Stadt in the GDR to produce ultrasound instruments for tumour extraction and aspiration, for the insertion of stomatological leaf implants, for percutaneous lithotrips of kidney stones and for the surface treatment of septic wounds.

Blade Implantation↗
PubMed1990

[Site and incidence of multiple cancers in patients with squamous cell carcinomas of the upper aerodigestive tract].

The etiology of multiple primary cancers has not been clearly elucidated, although some pathogenic factors are known. The studies reported here include 796 patients who, between January 1970 and March 1989, presented with a carcinoma of the upper aerodigestive system. The charts of 687 patients were analyzed retrospectively; 109 patients were studied prospectively by systematic pretherapeutic panendoscopy. Multiple primary cancers were found in 76 cases (9.5%), 33 patients had synchronous cancers, and 43 had metachronous cancers. In the prospective study, the incidence of multiple cancers was higher (13.7%) than in the retrospective group (8.8%). Synchronous primaries were more frequent in the prospective study (8.2%) than in the retrospective analysis (3.4%). Second primaries were mostly found in the esophagus, the hypopharynx, the buccal cavity, and the lung. The authors also examined whether the anatomic location of the second primary cancer can be related to the site of the first. The five-year survival rate among patients with synchronous cancers (18%) was lower than among patients with metachronous cancers (41%). The prognosis for synchronous cancers deteriorates if the planned treatment has to be modified following the discovery of a second primary. Systematic pretherapeutic panendoscopy should be used to help detect early asymptomatic second primaries which might be missed during clinical examination.

Carcinoma, Squamous Cell↗
PubMed1990

[Precipitating factors for shunt insufficiency in post-hemorrhagic hydrocephalus in the premature infant].

Between January 1984 and March 1989 twenty-seven low birth weight infants (mean birth weight 1351 gm, mean gestational age 30 weeks) required shunts after development of a posthaemorrhagic hydrocephalus. Revision of the shunt occurred in 78% of the patients with a range of 1 to 11 revisions. Obstruction of the ventricular catheter was the main cause of mechanical complications that occurred in 75%. Preterm infants weighing less than 1000 gm revealed an enormous infection rate of 71%. Initial shunt placement in the first 8 weeks of life was more likely to need shunt revision (94%) than that placed at older age (44%). There was no difference between the type of shunt and percentage of shunt revision, but the Heyer-Schulte system in comparison with the Codman Uni shunt was more likely to have mechanical complications. Infants with Grade IV haemorrhage required the same percentage of revisions as those with Grade III haemorrhage. There was no association between preoperative therapy and the need for shunt revision. A great amount of erythrocytes and very low glucose levels in the preoperative CSF were more likely to predict shunt revision than predicted by the CSF protein.

Birth Weight↗
PubMed1990

The influence of selected tannin-containing plant species on the tenacity of pathogenic bacteria in an in-vitro rumen system. 1. Communication: the influence of selected plant species on the tenacity of Cl. perfringens.

The effect of plant species containing tannins on the tenacity of Cl. perfringens was elucidated. Trials were purchased in physiological saline solution and in a rumen-fluid-medium under anaerobic conditions. The results obtained show, that within minutes the tenacity of Cl. perfringens can be reduced by some of the tested plant material not only in physiological saline solution but also in a rumen-fluid-medium. The results indicate that the reaction of some vegetable tannins and Clostridium perfringens germs is a specific one and could be used in controlling diseases caused by Clostridium perfringens.

Acacia↗
PubMed1990

Inhibitory role of dentate hilus neurons in guinea pig hippocampal slice.

1. Current and voltage-clamp recording of CA3/CA4 pyramidal neurons, hilar neurons, and granule cells or pairs of these neurons were used to study the generation of Cl-dependent and K-dependent inhibitory postsynaptic potentials (IPSPs) in the guinea pig hippocampal slice preparation. 2. A sequence of an early Cl-dependent and a late K-dependent IPSP was evoked in CA3 neurons by electrical stimulation from the stratum moleculare of the dentate gyrus, the hilus, and the stratum oriens/alveus. Blockade of glutamatergic excitation by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 10 microM) and D(-)-2-amino-5-phosphonovaleric acid (APV, 30 microM) abolished IPSPs evoked from the stratum moleculare of the dentate gyrus, but IPSPs could still be evoked from the hilus and the stratum oriens/alveus. 3. Repetitive giant IPSPs, which consisted of Cl-dependent and K-dependent components, were evoked by bath application of 4-aminopyridine (4-AP, 10-50 microM) in CA3 neurons and in granule cells. Giant IPSPs were blocked by bath-applied tetrodotoxin (TTX). In addition, 4-AP hyperpolarized CA3 neurons in a Cl-dependent and picrotoxin-sensitive way. 4. Focal application of TTX to the dentate gyrus or the hilus considerably reduced the amplitude of giant IPSPs evoked by 4-AP in CA3 neurons. In hilar neurons, 4-AP evoked repetitive bursts, eventually, but not necessarily intermingled with giant IPSPs. Bursts were observed in hilar neurons in presence as well as absence of CNQX and APV. 5. In paired recordings, bursts in hilar neurons induced by 4-AP occurred simultaneously to giant IPSPs in granule cells and CA3 neurons, and giant IPSPs in granule cells occurred simultaneously to giant IPSPs in CA3 neurons. Blockade of glutamatergic excitation by CNQX and APV did not abolish this synchrony. 6. 4-AP-evoked Cl- and K-dependent IPSPs were, unlike electrically evoked IPSPs, not strictly coupled: some 20% of large IPSPs and up to 90% of small IPSPs were either Cl or K dependent. In granule cells K-dependent components either preceded or followed Cl-dependent components. 7. K-dependent IPSPs only could be evoked in CA3 neurons by focal application of 4-AP (1 mM) to the hilus, the stratum lacunosum moleculare or the stratum pyramidale. Wash out of Ca for 15-20 min blocked the Cl-dependent but not the K-dependent component of giant IPSPs evoked by bath-applied 4-AP.(ABSTRACT TRUNCATED AT 400 WORDS)

4-Aminopyridine↗
PubMed1990

Influence of different half-field stimulations on the pattern reversal visually evoked cortical potential.

In 30 healthy subjects the visually evoked cortical potential following full-field and upper, lower, temporal and nasal half-field pattern-reversal stimulation was registered. No significantly differing latencies for peak N90 were to be seen. The responses of peak P120 for upper half-field stimulation showed a significantly longer latency than for full-field, lower, temporal and nasal half-field stimulation. Responses to upper and lower half-field stimulation showed no potential reversal. Nasal and temporal half-field stimulation evoked responses with no significantly differing P120 latencies.

Adolescent↗
PubMed1990

Cerebral aneurysms: assessment of 377 cases (1956-1982).

A review of 177 patients with cerebral aneurysms is made, out of whom 106 with ruptured aneurysms were examined, whose operational timing and prognostic chances were well documented (group B, 1979-1982) and in part updated to 1984. Furthermore, relevant data of a previous series of 200 cases of cerebral aneurysm, treated between 1956-1978 were used (group A). The patients were graded according to Hunt and Hess, assessing the risks involved. The percentages of recurrent bleeding were in group A 36.5% and 28% in group B. The incidence of vasospasm (as seen in angiography) was in group B 39.6% (42/106 patients). The highest rate of vasospasm in the spasm group division B was found to occur in the second and third week after subarachnoid haemorrhage and amounted to 64.7% and 62.5%. A pre-operatively present vasospasm had no negative effects on the mortality rate, but influenced the outcome for the survivors effectively. The total mortality in group A was 22.5% and in group B 11.7%. Timing of the operation among patients in Hunt and Hess-grades I and II needs to discussion. The surgical position of patients in grade V is also certain. What remains to be discussed and needs attention is grade III and patients in grade IVa. Here the time of operative intervention must be planned individually depending on the course of the neurological status.

Cerebral Angiography↗
PubMed1990

Management of giant aneurysms.

Technical aspects and anatomical difficulties involved in the management of this entity and the risks associated give giant aneurysms a special place in the treatment of aneurysms as a whole. The direct attack needs careful planning and the right choice of instruments, especially clips. In spite of the progress in recent years, the rate of mortality is still very high. The indirect approach requires in many cases the occlusion of a major cerebral vessel, which in some cases could result in cerebral ischemia. However, by means of extra-intracranial by-pass operation this risk could be reduced. The method of balloon embolisation has progressed recently. This procedure brings the least discomfort to the patient. Results of this method of treatment must be observed critically for future assessment.

Adolescent↗
PubMed1990

Liquid-liquid partition chromatography of biopolymers in aqueous two-phase systems.

The theoretical and practical principles of liquid-liquid partition chromatography (LLPC) applying aqueous two-phase polymer systems are presented. The method is based on support materials which bind one of the two aqueous phases with high preference and reject the other. This selectivity is obtained by making use of incompatibilities between polymers grafted on support particles and polymers in solution. Applications of the separation technique to the fractionation of protein and nucleic acid mixtures are shown. For the DNA-fractionation according to base composition an affinity partition chromatography using polyethylene glycol-bound base-specific complexing agents has been developed which exhibits a resolution superior to all other methods known.

Animals↗