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Biomedical subjects

W Steiner

Publications and source records attributed to W Steiner.

At least 55 records · Page 3Linked to original sources
PubMed1996

Cloning and characterization of the gene for the thermostable xylanase XynA from Thermomyces lanuginosus.

A thermostable xylanase from the filamentous fungus Thermomyces lanuginosus (DSM 5826) was purified. This enzyme has an apparent molecular weight of 24-26 kDa as determined by SDS polyacrylamide gel electrophoresis. cDNA and genomic DNA fragments coding for this enzyme were cloned and sequenced. The cDNA contains an open reading frame encoding a polypeptide of 225 amino acids and was functionally expressed in E. coli as a LacZ fusion protein. Comparison of the cDNA sequence with the genomic DNA sequence showed that the xylanase was encoded by two exons interrupted by an intron of 106 bp. Comparison of the deduced amino acid sequence to other published xylanases revealed high homology to xylanases of the family G glycanases.

Amino Acid Sequence↗
PubMed1996

Selective neck dissection in the management of squamous cell carcinoma of the upper digestive tract.

Selective neck dissection has been used clinically in elective treatment of carcinoma, although many surgeons continue to advocate modified radical or radical neck dissection for therapeutic management of the neck. In a retrospective study 167 previously untreated patients were reviewed following curative laser microsurgical resections of oral or pharyngeal primary tumors and a unior bilateral selective neck dissection. In all, 221 (54 bilateral) neck dissections were performed. In patients with oral primary disease lymph nodes of levels I-III were removed, while nodes in levels II and III were removed in patients with pharyngeal tumors. Level IV was dissected when several metastases were suspected during operation. The posterior triangle was not dissected. Lymph nodes were histopathologically negative in 73 patients and positive in 94 patients. Twenty-five of these latter cases had pN1 disease, 55 had pN2b disease and 10 had bilateral lymph node metastases. Twenty patients in the pN0 group and 63 patients in the pN+ group received postoperative radiotherapy (to 56.7 Gy to the primary site and 52.5 Gy to the neck). With a median follow-up interval of 34 months, recurrence in the dissected neck occurred in 3 of 73 patients (4.1%) with pN0 disease and 6 of 90 patients (6.6%) with pN+ necks. Four patients with pN+ necks had simultaneous recurrences at the primary site. The addition of adjuvant radiotherapy seemed to improve disease control in the neck and improve overall survival in patients with an unfavorable prognosis due to multiple metastases or metastases with extracapsular spread.

Adult↗
PubMed1996

Time-dependent changes of insufficiency fractures of the sacrum: intraosseous vacuum phenomenon as an early sign.

Sacral insufficiency fractures develop over a period of time and show time-dependent changes. We report on 15 CT examinations of 5 patients with early-stage insufficiency fractures of the sacrum. In 4 patients only irregular sclerosis without distinct fracture lines was present in 7 of 8 fractures. Of these 4 patients; 3 exhibited intraosseous gas inclusions in a ventral part of a lateral mass; 5 of 8 fractures disclosed a ventral cortical break. When distinct fracture lines had developed in 1 patient, intraosseous vacuum phenomenon had disappeared. Fracture lines evolve over weeks to months and show central bone absorption. The fractures can heal as demonstrated in 4 of 6 fractures in 3 patients, can persist over 1 year without significant changes or can progress to pseudoarthrosis with bone destruction similar to neuropathic joint disease. Intraosseous vacuum phenomena can persist to this stage. Intraosseous vacuum phenomenon is recognized as a potential finding in the early stage of sacral insufficiency fracture, which also is true for irregular sclerosis and ventral cortical disruption.

Follow-Up Studies↗
PubMed1996

Incidence of and risk factors for delirium among psychiatric inpatients.

OBJECTIVE: The presence and effects of delirium among psychiatric patients are not well understood. This study investigated incidence rates and risk factors for delirium among hospitalized psychiatric patients. METHODS: The charts of 199 patients admitted over a one-year period to a tertiary care teaching hospital were retrospectively reviewed. Demographic and medication variables were analyzed using multiple logistic regression. Delirium was diagnosed retrospectively using DSM-III-R criteria. RESULTS: The overall incidence of delirium in the study sample was 14.6 percent. Delirium was most common among patients with schizophrenia and bipolar disorder; patients with bipolar disorder had the highest incidence (35.5 percent). Only 48 percent of delirious patients were actually recognized as having delirium at the time it occurred. Antiparkinsonian medications were the only medications significantly associated with delirium; lithium was not an independent risk factor. Older age was the only significant demographic risk variable. The hospital stays of patients with delirium were 62.1 percent longer than those of patients without delirium. CONCLUSIONS: Patients with bipolar disorder appeared to be at higher risk for developing delirium, whether or not lithium was used in treatment. This finding may reflect an inherent predisposition to delirium among these patients. Alternatively, the combination of medications used in treating patients with bipolar disorder may be a risk factor.

Adult↗
PubMed1995

[The percutaneous treatment of surgical and catheter-angiographic vascular complications].

PURPOSE: Technical innovations of angioplasty have introduced new therapeutic options in the treatment of symptomatic arteriosclerotic disease. Atherectomy devices, aspiration catheters and vascular endoprostheses can be used not only for angioplasty purpose but also for correction of iatrogenic dissections and thromboembolic complications. MATERIAL AND METHODS: 54 patients with vascular complications after surgical (n = 7) and percutaneous (n = 47) interventions were observed in a 5 years period. The complications included acute dissections in 34 cases, acute thrombosis in 4 cases, distal embolism after angioplasty in 14 cases, and two cases with arterial rupture after balloon dilatation. RESULTS: 34 patients with dissections and 18 patients with acute thrombosis were treated. Stent implantation for repair of vessel dissection was successful in 33 of 34 cases. Percutaneous catheter aspiration in combination with local thrombolysis was successful in 4 cases with local thrombosis. Distal emboli after angioplasty were successfully removed using aspiration catheters in 13 of 14 patients. Vessel rupture after angioplasty was closed with prolonged balloon dilatation in two patients avoiding emergency surgery. CONCLUSION: Using newly developed intravascular technologies such as atherectomy, stents, and catheter aspiration, many iatrogenic complications after vascular surgery or vascular interventions can be treated. These technologies should be available in every radiology department performing angioplasty.

Acute Disease↗
PubMed1995

[Chemoembolization in primary liver cell carcinoma. Results of a prospective study].

A remarkable progress was made in the palliative treatment of unresectable hepatocellular carcinoma using transcatheter arterial chemoembolization (TAC). The combination of doxorubicin as cytotoxic drug and of Lipiodol as carrier, which is selectively accumulated within the tumors is an effective treatment. Prolonged survival has been demonstrated in several clinical studies. In a prospective trial the effect of regional TAC with temporary ischemia of the liver was evaluated concerning liver function, systemic reactions and tumor response. Temporary ischemia of the liver was well tolerated even in patients with liver cirrhosis. Revascularization of the liver after TAC was observed in all cases. Systemic side effects of the cytotoxic drug were mild. In patients with Child C cirrhosis or tumor volume of more than 60% of the liver no impact of the treatment on the survival time was observed. In the entire patient group a survival rate of 70% after 15 months was achieved.

Aged↗
PubMed1995

[Percutaneous transluminal angioplasty of arterial stenoses after kidney transplantation].

Over a period of 11 years, percutaneous transluminal angioplasty (PTA) was performed in 47 patients with post-transplantation renal artery stenosis. In 42 of 47 patients (89%) PTA was technically successful. Complications or technical failure (n = 5) were observed in the beginning of the series and were due to technical problems. Within a five-year follow-up period in 33 patients, blood pressure (BP) remained constant in 18% and mean pressure was improved in 48%. In 33%, normal BP was reached without any need for medication. Systolic and diastolic BP were reduced from 175.9/105.7 (mean values) before PTA to 146.9/91.0 six months after PTA. Depending upon the initial value, serum creatinine was reduced after PTA by from 0.0 to 1.0 mg/dl with noticeable difference between individual values. An account of this effect, renal function was of reduced value for controlling the effectiveness of PTA. The morphology of the stenoses corresponded only partially with the clinical results: in five patients mean BP after successful PTA remained constant, while two patients with reduced therapeutic result (remaining stenosis > 30%) had either markedly improved BP (n = 1) or normal BP (n = 1). The technical improvement of PTA instrumentation has broadened the spectrum of indications and improved the safety of the procedure.

Adolescent↗
PubMed1995

[3-phase spiral CT--a new noninvasive procedure for the differentiation of multifocal liver lesions].

Dynamic CT is an established method for the differentiation of focal liver lesions by monitoring the contrast enhancement. It is especially restricted in the assessment of small and multiple lesions due to respiratory organ movements. Spiral-CT allows the examination of large volumes in the breathhold technique. Spiral-CT with controlled i.v. contrast media administration can be used for the assessment of the entire liver in distinct phases of perfusion. We describe the use of this new technique in a patient with multifocal nodular hyperplasia (FNH), for whom assessment with dynamic CT was not suitable. The lesions were first located with a conventional contrast-enhanced CT-scan. The impossibility to assess all the lesions with dynamic CT led to the decision to perform a three-phase spiral-CT with three sequential scans (native, arterial, and portal perfusion phase). The entire liver was scanned after power injector-controlled i.v. administration of contrast media with the following parameters: 1) arterial phase: 70 ml contrast media, 2 ml/s, start delay 18 s; 2) portal phase: 80 ml contrast media, 2 ml/s, start delay 60 s; slice 8 mm, table feed 8 mm, increment 4 mm; 24 s of breathhold data acquisition.

Adult↗
PubMed1994

Cellulose hydrolysis by the cellulases from Trichoderma reesei: adsorptions of two cellobiohydrolases, two endocellulases and their core proteins on filter paper and their relation to hydrolysis.

Separate binding of several purified cellulolytic components of Trichoderma reesei on to filter paper was studied and concomitant hydrolysis rates evaluated. Enhancement of mass transfer from the bulk liquid to the solid substrate by agitation has two different effects on adsorption depending on the type of enzyme: (i) the fraction of cellobiohydrolase II (CBH II) and endoglucanase III (EG III) bound at equilibrium is increased, whereas (ii) the rate but not the extent of cellobiohydrolase I (CBH I) and endoglucanase I (EG I) adsorption is affected. The adsorption of CBH I core, a component lacking the cellulose-binding domain (CBD), is, however, not significantly influenced by mass transfer. The CBH I interdomain peptide (present in CBH I core b) does not participate in adsorption but enhances stability. The adsorption of CBH I core proteins is a fully reversible process whereas that of the intact CBH I is not. Thus, the interaction of the CBD with filter paper apparently accounts for the mass-transfer-limited binding rate and also for the irreversible adsorption of intact CBH I. Adsorption isotherms at 50 degrees C indicate very similar relative association constants for the intact cellulases (0.24-0.30 l/g of cellulose), but drastically reduced values for CBH I core proteins (0.03 l/g of cellulose). The specific activities of adsorbed CBH I and of its core proteins are identical and a linear relationship between adsorption and rates of hydrolysis is found only for these enzymes. Thus, non-productive binding on to cellulose seems evident in the case of CBH II and EG III but not CBH I.

Adsorption↗
PubMed1994

Cellulose hydrolysis by the cellulases from Trichoderma reesei: a new model for synergistic interaction.

The hydrolysis of Whatman no. 1 filter paper by purified cellulolytic components from Trichoderma reesei and the synergistic action of binary combinations of these enzymes on the same substrate were investigated. At 20 milligrams filter paper, enzyme concentrations needed to obtain half-maximal hydrolysis rates (KE values) were in the 3-4 microM range for the cellobiohydrolases (CBHs) and 0.05-0.10 microM for the endoglucanases (EGs). Catalytic-core proteins of CBH I and EG III, lacking the cellulose-binding domain, exhibit KE values 2.3 and 5.1 times higher than those of the intact enzymes. In synergistic combinations of two cellulases, the KE value of at least one enzyme was 3-10-fold reduced. CBH I/CBH II and CBH I/EG III combinations showed the most powerful synergism, and optimal ratios were a function of the total protein concentration. Results obtained in activity and adsorption assays using filter paper pretreated with one component, followed by inactivation and subsequent hydrolysis with the same or another cellulase component, point to a sequential enzymic attack of the cellulose and seems consistent with the mathematical model presented.

Adsorption↗
PubMed1994

Percutaneous transjugular intrahepatic stent shunt for treatment of intractable varicose bleeding in paediatric patients.

UNLABELLED: Two 10-year and 11-year-old children with oesophageal and gastric varicose haemorrhage unresponsive to medical treatment and repeated endoscopic sclerotherapy underwent percutaneous transjugular intrahepatic portosystemic shunting (TIPSS). A newly developed introducing system was used. The procedure was performed to avoid the increased risk of emergency liver transplantation in children with hepatic failure. Immediately after the procedure bleeding stopped and the patient's condition improved. Ascites disappeared and liver function improved. The stent shunt was shown to be patent by angiography and Doppler ultrasound for a follow up period of more than 1 year. CONCLUSION: TIPSS may be of benefit in children with severe portal hypertension. It allows control of intractable bleeding, and stabilizes the patients preparing them for subsequent elective orthotopic liver transplantation.

Child↗
PubMed1994

Phototherapy in the treatment of depression in the terminally ill.

Research in affective disorders has shown that there is a clear link between mood and light exposure, and that exposure to bright wide-spectrum light (phototherapy) may be an effective antidepressant treatment in some clinical situations. Cancer patients, especially those in the terminal phase of illness, have a high incidence of depression. Furthermore, their mobility is often severely reduced, resulting in little exposure to direct sunlight. We report the use of phototherapy in three terminally ill patients to alleviate symptoms of depression.

Aged↗
PubMed1994

Stent-angioplasty of an anastomotic stenosis of the pulmonary artery after lung transplantation.

Anastomotic stenosis of the pulmonary artery after lung transplantation is a rare complication, which commonly necessitates surgical correction. Transesophageal Doppler sonography and pulmonary arteriogram are standard diagnostic means for visualization of venous and arterial anastomoses. Balloon dilatation combined with implantation of a vascular endoprosthesis was successfully used for treatment of severe anastomotic stenosis of the pulmonary artery after lung transplantation.

Anastomosis, Surgical↗
PubMed1994

[Special aspects of histopathologic diagnosis in laser microsurgery of cancers of the upper aerodigestive tract].

Histological examination of CO2 laser-resected specimens reveals a thin layer of carbonisation, beneath which the cellular architecture is preserved, permitting adequate assessment. With early staged laryngeal, oral and pharyngeal carcinomas, it is usually possible to remove the tumour as a single block, and the margins can be studied by parallel histologic sections. Advanced tumours, regardless of their localisation, demand resection in several blocks. Each tissue block is carefully orientated and the deep surface of every specimen is stained. Accurate mapping of every block is essential to enable the surgeon to identify the precise location of each specimen in the patient. The specimens are vertically sectioned after paraffin wax embedding. Grading, depth of invasion, lateral and basal margins are examined. Like in conventional surgery, it is technically impossible to examine all margins of a large specimen. With vertical sections only limited information can be obtained about lateral and basal margins. If deep tumour infiltration reaches cartilage or bony structures, clear microscopic margins are difficult to prove after laser resection. Finally it must be possible for the surgeon to recreate a complete, 3-dimensional mosaic of the entire lesion to achieve accurate pT-staging.

Carcinoma, Squamous Cell↗