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Biomedical subjects

R M Huber

Publications and source records attributed to R M Huber.

At least 37 records · Page 2Linked to original sources
PubMed2004

No evidence of cerebral oedema in severe acute mountain sickness.

In a randomized, double-blind cross-over study 10 subjects were exposed to a simulated altitude of 4500 m for 10 h after administration of placebo, acetozolamide (250 mg bid) or theophylline (250 mg bid). T2-weighted magnetic resonances images (MRI) and diffusion weighted MRI were obtained directly after exposure to altitude under hypoxic conditions. Although eight of 10 subjects had moderate to severe acute mountain sickness (AMS), we found no evidence of cerebral oedema, irrespective of the medication taken. Almost all subjects showed a decrease in inner cerebrospinal fluid (iCSF) volumes (placebo - 10.3%, P= 0.02; acetazolamide - 13.2%, P= 0.008, theophylline -12.2%, n.s.). There was no correlation between AMS symptoms and fluid shift. However, we found a significantly positive correlation of large (>10 ml) iCSF volume and more severe AMS after administration of placebo (r = 0.76, P= 0.01). Moderate to severe AMS after high altitude exposure for 10 h is associated with a decreased iCSF-volume independent of AMS severity or medication without signs of cerebral oedema.

Acetazolamide↗
PubMed2004

Theophylline and acetazolamide reduce sleep-disordered breathing at high altitude.

A randomised, double-blind, placebo-controlled study was conducted to evaluate the effects of theophylline and acetazolamide in the treatment of sleep-disordered breathing (SDB) after fast ascent to high altitude (3,454 m). The study was conducted at a high-altitude research laboratory and included 30 healthy male volunteers. Study medication was either oral slow release theophylline (2x250 mg x day(-1)), oral acetazolamide (2x250 mg x day(-1)) or a matched placebo tablet. Polysomnographic measurements were performed during two consecutive nights, and acute mountain sickness, pulse rate, oxyhaemoglobin saturation and arterial blood gases were assessed three times a day. Without active medication, the apnoea/hypopnoea index (AHI) was highly pathological (median 16.2 x h(-1), range 2-92). Both theophylline and acetazolamide normalised SDB (median AHI 2.5 x h(-1), range 0-11; 4.2 x h(-1), range 0-19, respectively) and reduced oxyhaemoglobin desaturations during sleep (median desaturation index placebo 41.5 x h(-1), range 6-114; acetazolamide 6.5 x h(-1), range 3-28; theophylline 8.5 x h(-1), range 3-32). Compared with the high amount of central apnoeas or hypopnoeas, the number of obstructive events during sleep was very low in all groups (<4 x h(-1)). In contrast to theophylline, acetazolamide significantly improved basal oxyhaemoglobin saturation during sleep (86.2 +/- 1.7% versus 81.0 +/- 3.0%). The authors conclude that both oral slow release theophylline and acetazolamide are effective to normalise high-altitude sleep-disordered breathing.

Acetazolamide↗
PubMed2003

[Asthma attack out of control--what to do? Therapy of acute asthma exacerbation depends on severity].

Treatment of acute asthma exacerbation is determined by the severity of the attack, making it necessary to grade the latter using objective parameters such as clinical symptoms, respiratory rate, heart rate, oxygen saturation and FEV1 or PEF. Severity grading is also essential for the further management--need for early hospitalization--in particular in the case of risk patients. Apart from the treatment of hypoxia, first-line treatment comprises bronchodilation with beta-2-agonists. Anti-inflammatory measures applying corticosteroids are indicated, in particular in moderate to severe exacerbation, while inhalative anticholinergics and theophyline are available in addition when primary treatment fails, and in the case of severe exacerbations.

Acute Disease↗
PubMed2003

Effects of single-dose irradiation on bronchial epithelium: a comparison of BEAS 2B cell monolayers, human organ cultures, and Goettinger minipigs.

To assess the effects of radiation on bronchial epithelium, BEAS 2B cells cultured as monolayers and human bronchial epithelium cultured as organ cultures were exposed to single doses of 0, 10 and 30 Gy. The lactate dehydrogenase in the supernatant of the BEAS 2B cells increased markedly 24 h after irradiation, whereas in the organ cultures only a minor increase was found after 48 h. The nucleosomes in the supernatant of the BEAS 2B cells showed a massive increase in response to irradiation, whereas in the organ cultures no change could be seen. The number of BEAS 2B cells was dramatically diminished after 96 h, whereas in the organ cultures a smaller decrease was observed no earlier than 21 days after irradiation. To assess the effects of brachytherapy in bronchial epithelium in vivo, brachytherapy with 30 Gy was performed in Goettinger minipigs, and histological sections of the bronchi were analyzed for morphological alterations and cell numbers. After 2 weeks, only slight cell damage was observable, and after 3 weeks, moderate morphological changes and decreased cell numbers were found. However, after 8 weeks, the epithelium had nearly regained its normal structure. We conclude that the bronchial epithelium has a remarkably high radioresistance and that organ cultures, but not monolayers of BEAS 2B cells, reflect the effects of radiation in vivo.

Animals↗
PubMed2002

[Interdisciplinary interventional therapy for tracheobronchial stenosis with modern metal net stents].

STUDY OBJECTIVES: Assessment of the therapeutic potential of tracheobronchial stenting for obstructive tracheobronchial disease, in-vivo comparison of different stent types and development of helpful criteria for choosing the suitable stent type. MATERIAL AND METHODS: Prospective case analysis. Between 1993 and 1999 53 stents were implanted into the tracheobronchial system of 39 consecutive patients with benign or malignant airway obstruction. Every single stent (26 Strecker Stents, 18 Wallstents, 6 Accuflex Nitinolstents, 1 Dumon-, 1 Rüsch- and 1 Palmazstent) was recorded in an unified database. Analysis comprised clinical effectiveness, lung function if possible, relevant complications and radiologic follow-up parameters. The probability of their remaining within the tracheobronchial system, of their remaining undislocated and uncompressed was calculated using Kaplan-Meier analysis for three stent types. RESULTS: Stent placement proved itself to be an effective treatment in 86 % of the patients. Resistance could be normalized in 9/9 patients. Kaplan-Meier analysis clearly revealed a higher probability for the Wall- and Nitinolstent to remain within the tracheobronchial system and to remain uncompressed. Dislocation also occurred more rarely. Explantation of the Wallstent, however, if desired, was much more difficult compared to the Strecker stent. The Wallstent also occasionally led to the formation of granulation tissue especially at the proximal stent end and, as such, required reintervention. CONCLUSION: Any of the 3 stent types proved to be an effective therapeutic option in the management of obstructive tracheobronchial disease. Choise of the stent type should be determined through definition of the therapeutic intention. It is useful to distinguish between (a) benign stenosis, (b) malignant stenosis but curative therapeutic situation and (c) malignant stenosis in a palliative therapeutic situation with limited life expectancy. In spite of its superior mechanical properties the Wallstent is rather suited for a palliative situation because explantation may be difficult. The Strecker Stent requires more reinterventions but removal is easy to perform. The Nitinolstent possibly represents a reasonable compromise.

Adolescent↗
PubMed2001

Long-term stent implantation in a case of relapsing intrathoracic Ewing-sarcoma.

The overall prognosis of relapsing Ewing sarcoma is poor and therapeutic options can be limited by extensive chemotherapeutic pretreatment. We report on a case of a 27-year-old male, presenting with a large mediastinal mass and malignant pleural effusions. 5 years prior peripheral Ewing sarcoma had been treated according to the CESS 86 protocol. Relapse chemotherapy was initiated (CESS protocol) but tumor progression led to stenoses of both main bronchi. At this critical point, 2 Strecker tantal stents were placed endoscopically to prevent suffocation and provide the time for further chemotherapy, regardless of the poor overall prognosis. Complete remission was achieved by high-dose ifosfamide, surgery, radiotherapy and adjuvant ifosfamide. In spite of possible complications of long-term stent implantation, the stents were not removed until 4 years later when stent dislocation occurred. After removal, the stents were epithelialized and electron microscopy demonstrated structural integrity of the stent. The patient has remained in complete remission since (6 years).

Adult↗
PubMed2001

Laser resistance of expandable metal stents in interventional bronchoscopy: an experimental evaluation.

BACKGROUND AND OBJECTIVE: Nd-YAG non-contact laser therapy is used to eliminate recurrent tumor tissue within airway stents. This study was performed to determine maximum exposure time until the stent wire is destroyed as well as exposure time necessary to deliberately fracture the wire mesh. STUDY DESIGN/MATERIALS AND METHODS: Strecker stents, Wallstents, and Nitinol Accuflex stents were implanted into pig bronchi. Then Nd-YAG laser light was directed to the stent wires at different power levels. Portions of the stent surrounded by bronchial tissue as well as bare wires were investigated. RESULTS: The Strecker stent and the Wallstent revealed a considerably higher laser resistance than did the Nitinol Accuflex stent. At 15 W, minimum exposure time until wire destruction was 4.6 and 6.3 s for the Strecker stent and the Wallstent respectively. In contrast, the Nitinol Accuflex stent tolerated only 1.7 s. CONCLUSIONS: Laser therapy with bronchial wire stents can be carried out at low power levels. It should, however, be avoided in the case of Nitinol Accuflex stents due to their low heat tolerance.

Alloys↗
PubMed2001

Metal airway stent implantation in children: follow-up of seven children.

Long segment malacia of the trachea or main stem bronchi in children is not always suitable for surgical correction; patients may therefore remain ventilator-dependent and/or experience severe obstructive crises. We treated 7 children (ages, 4 months to 9 years) with extreme structural central airway obstruction with stent implantations. Six were mechanically ventilated; 5 had frequent life-threatening obstructive spells requiring deep sedation or paralysis. Diagnoses were: syndrome-associated tracheobronchomalacia (n = 4), malignancy infiltrating the carina (n = 1), congenital tracheal stenosis (n = 1), and tracheobronchial compression by a malpositioned aorta (n = 1). Six tracheal and 13 bronchial stents were endoscopically placed. The prostheses included mesh titan (n = 5), the newer shape memory material nitinol (n = 13), and 1 Y-shaped carina stent. Follow-up was reported for 7 weeks to 72 months. All patients showed marked improvement of their respiratory obstruction. Six children were weaned at least temporarily from ventilation. No significant bleeding, stenosis, or perforation was observed. Seven stents were changed after up to 14 months. Three children are well and at home. In 2 children airway stabilization was successful, but they later died from causes unrelated to stent placement, and 2 children died due to generalized airway disease. Soft metal mesh airway stents can offer a therapeutic option in life-threatening inoperable obstruction of the trachea and main stem bronchi in children.

Airway Obstruction↗
PubMed2001

Sequential chemo- and radiochemotherapy with weekly paclitaxel (Taxol) and 3D-conformal radiotherapy of stage III inoperable non-small cell lung cancer. Results of a dose escalation study.

The purpose of this study was the determination of the maximum tolerable dose (MTD) of weekly paclitaxel (PX) in combination with 3D-conformal radiotherapy in non-small cell lung cancer (NSCLC) and the evaluation of side effects, patient outcome and tumor response. Thirty-eight patients with inoperable NSCLC, UICC-stage IIIA (n=14)/IIIB (n=24) received two cycles of induction chemotherapy with PX/carboplatin followed by combined radiochemotherapy (60 Gy/6 weeks) with weekly PX which was escalated in cohorts of four patients until dose limiting toxicity (DLT) was reached. Starting level was 40 mg/m(2). 3D-conformal radiotherapy was applied in all patients. Toxicity was determined by WHO criteria. Patients were followed-up 3-monthly. Thirty eight patients have entered the study, 34 patients are evaluable. DLT was esophagitis III degrees, requiring interruption of radiotherapy and was reached at the PX 70 mg/m(2). Two hypersensitivity reactions (50 mg/m(2)) and one leucopenia III degrees (60 mg/m(2)) were observed. Only one patient (60 mg/m(2), 50 Gy) completely aborted treatment. The pneumonitis rate was between 21 and 36% but showed no clear correlation with PX dose. Tumor response (PR and CR) defined by CT-scan 6 weeks following radiotherapy was 88% (30/34). The 1- and 2-year survival rate is 73% and 34%. We conclude that the MTD of weekly PX with 60 Gy normofractionated radiotherapy is 60 mg/m(2). The DLT is esophagitis. Response and survival data of this sequential/combined approach are promising. A minor increase of pulmonary toxicity of irradiation is suspected.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2001

[PET - Quo vadis?].

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Fluorodeoxyglucose F18↗