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Biomedical subjects

S M Lang

Publications and source records attributed to S M Lang.

At least 19 recordsLinked to original sources
PubMed2006

[Effectiveness of inpatient pulmonary rehabilitation (AHB). Results of a multicenter prospective observation study].

BACKGROUND AND OBJECTIVE: The value of pulmonary rehabilitation in the treatment of chronic obstructive pulmonary disease (COPD) is well accepted. However, there are no data on the efficacy of in-patient rehabilitation instituted within 14 days after an acute disease episode, as practised in Germany. It was the purpose of this multi-centre prospective study to assess changes in lung function, exercise capacity, symptoms and disease-related quality of life (QoL) in patients discharged from hospital for an episode of worsening COPD or asthma, pulmonary embolism, pneumonia or treatment of lung cancer. PATIENTS AND METHODS: 207 patients (mean age 60 13 years) with COPD (n=86), pneumonia (n=42), lung cancer (n=24), asthma (n=14), pulmonary embolism (n=7) or other pulmonary disease (n=34) were included. Measurements of lung function, exercise capacity and disease-related QoL were carried out at the beginning and end of rehabilitation. Socio-economic data and disease-related QoL measurements were recorded again after 2 months. RESULTS: Rehabilitation led to a significant improvement of lung function, exercise capacity and QoL. Patients felt rehabilitation was efficacious (95%), to be recommended (99%) and important (100%). Improvement of QoL was maintained at two 2 months and only 16% of previously working patients had applied for retirement. CONCLUSIONS: The data demonstrate the clinically relevant benefit of in-patient pulmonary rehabilitation immediately after a period of acute illness. In view of these result and the known morbidity and mortality of patients with COPD after hospitalization for a period of acute illness, this form of pulmonary rehabilitation should be considered as standard treatment for these patients.

Adult↗
PubMed2005

Monitoring of expiratory flow rates and lung volumes during a high altitude expedition.

BACKGROUND: Data on lung volumes and changes in flow-volume spirometry at high altitude are few and do not provide comprehensive assessment of the occurring changes. This study characterizes alterations of the forced expiratory flow-volume curve (FEFV-curve) and lung volumes at increasing altitude. METHODS: FEFV-curve and lung volumes at increasing altitude were characterized by daily assessment of peak expiratory flow (PEF), forced expiratory volume in one second (FEV1), forced vital capacity (FVC) and maximal expiratory flow rates (MEF 25, 50, 75) at 25%, 50% and 75% of the FEFV-curve with a portable spirometer (turbinometric method) three times a day during an expedition to Mustagh Ata (7545m) in 15 healthy mountaineers. RESULTS: With increasing altitude FVC and FEV1 were reduced by up to 25% (74.8% / 74.6% of baseline) and MEF25 was reduced to 81.5% of baseline values. PEF initially increased up to 4451m and returned to baseline values above 5000m. After descent below 2000m, all values normalized within one day. There were weak negative correlations between AMSS and FEV1, FVC and PEF (r = -0.23, p<0.001). CONCLUSIONS: We found increasing pulmonary restriction at high altitude without a marked reduction of PEF. Assessment of the FEFV-curve at high altitudes with a portable spirometer is a practical method reflecting the true field situation and may provide clinically relevant information (impending pulmonary edema).

Adult↗
PubMed2005

Lung function in adults with cystic fibrosis at altitude: impact on air travel.

Current guidelines for air travel state that patients with chronic respiratory diseases are required to use oxygen if their in-flight arterial oxygen tensions (Pa,O2) drop below 6.6 kPa. This recommendation may not be strictly applicable to cystic fibrosis patients, who may tolerate lower Pa,O2 for several hours without clinical symptoms. Lung function, symptoms, blood gas levels and signs of pulmonary hypertension were studied in 36 cystic fibrosis patients at altitudes of 530 m and, after 7 h, 2,650 m. A hypoxia inhalation test (inspiratory oxygen fraction 0.15) was performed at low altitude in order to predict high-altitude hypoxaemia. Median Pa,O2 dropped from 9.8 kPa at low altitude to 7.0 kPa at high altitude. Mild exercise at a workload of 30 W further decreased Pa,O2. Two-thirds of all patients exhibited Pa,O2 of <6.6 kPa during exercise and, except for one patient, were asymptomatic. Patients were significantly less obstructed at an altitude of 2,650 m. Low forced expiratory volume in one second at baseline was associated with a low Pa,O2 at altitude. It is concluded that cystic fibrosis patients with baseline arterial oxygen tensions of >8.0 kPa safely tolerate an altitude of 2,650 m for several hours under resting conditions. The risk assessment of low in-flight oxygenation should encompass the whole clinical situation of cystic fibrosis patients, with special attention being paid to the presence of severe airway obstruction.

Adult↗
PubMed2004

[High prevalence of osteoporosis in adult cystic fibrosis patients].

BACKGROUND AND OBJECTIVE: In adult patients with cystic fibrosis bone metabolism may be altered by multiple mechanisms, such as abnormal calcium homeostasis, malnutrition, chronic inflammation or inactivity in the course of respiratory failure. In contrast to the high prevalence of osteoporosis in CF patients before lung transplantation, data from different CF collectives show great variation. It was the purpose of our cross-sectional study to determine changes in bone metabolism by measuring bone mineral density, and assessing calcium metabolism and clinical characteristics in adult patients (mean age 32 years) with cystic fibrosis. PATIENTS AND METHODS: Bone mineral density (quantitative digital radiography), parameters of calcium homeostasis and clinical characteristics were determined in 34 adult patients with cystic fibrosis. RESULTS: The mean age of the study population was 32 years (range 20 to 47; 21m: 13f). 13 patients had normal T-values (mean bone mineral density in young adults), whereas 11 patients (32 %) had osteopenia and 10 (29 %) had osteoporosis. Calcium homeostasis was abnormal in only one case. In contrast T-values were positively correlated with a low body mass index (p = 0.01) and a low one-second forced expiratory volume (FEV1) (p < 0.05). CONCLUSION: Decreased mineral bone density is a frequent complication in adult patients with cystic fibrosis, but does not occur inevitably even in long-standing disease (up to 47 years). In our cohort measurable alterations of calcium homeostasis could be avoided by consistent substitution policy. The main determinants of a low T-value were poor nutritional status, lowered serum calcium or phosphate concentrations and severely impaired lung function as indicator of the progression of the disease. Screening of adult patients with CF can be recommended especially in presence of malnutrition or poor lung function.

Adult↗
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↗
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

Effects of ultrapure dialysis fluid on nutritional status and inflammatory parameters.

BACKGROUND: Malnutrition and chronic systemic inflammatory response syndrome not only coexist in uraemia, but may also have a bi-directional cause-and-effect relationship. To evaluate the role of dialysate-related cytokine induction in inflammatory response and nutritional status, we conducted a prospective comparison of two dialysis fluids differing in their microbiological quality. METHODS: Forty-eight early haemodialysis patients were assigned to either treatment with conventional (potentially microbiologically contaminated) or on-line produced ultrapure dialysis fluid. Study parameters were bacterial growth, markers of systemic inflammation (C-reactive protein (CRP) and interleukin 6), and parameters of nutritional status (estimated dry weight, upper mid-arm muscle circumference, serum albumin concentration, insulin-like growth factor 1, leptin, and protein catabolic rate). Patients were followed for 12 months. RESULTS: There were no statistically significant differences in demographic and treatment characteristics, degree of bacterial contamination of the dialysate, markers of systemic inflammation, or parameters of nutritional status among the two treatment groups at recruitment. Changing from conventional to ultrapure dialysis fluid reduced significantly the levels of IL-6 (19+/-3 pg/ml to 13+/-3 pg/ml) and CRP (1.0+/- 0.4 mg/dl to 0.5+/-0.2 mg/dl), and resulted in significant increases in estimated dry body weight, mid-arm muscle circumference, serum albumin concentration, levels of the humoral factors, and in protein catabolic rate after 12 months. Continuous use of conventional dialysis fluid (median 40-60 c.f.u./ml) was not associated with significant alterations in markers of inflammation (IL-6 21+/-4 pg/ml vs 24+/-6 pg/ml, CRP 0.9+/-0.3 mg/dl vs 1.1+/-0.4 mg/dl) or of nutritional status at any time of the study. All differences in systemic inflammation and nutritional parameters observed during the study period (from recruitment to month 12) were significant between the two patient groups. CONCLUSIONS: Cytokine induction by microbiologically contaminated dialysis fluid has a negative impact on nutritional parameters of early haemodialysis patients. The microbiological quality of the dialysis fluid represents an independent determinant of the nutritional status in addition to known factors, such as dose of dialysis and biocompatibility of the dialyser membrane. Ultrapure dialysis fluid adds to the cost of the dialytic treatment, but may improve the nutritional status in long-term haemodialysis patients.

Aged↗
PubMed2000

Detection of K-ras and p53 mutations in bronchoscopically obtained malignant and non-malignant tissue from patients with non-small cell lung cancer.

Molecular screening may increase the likelihood to identify early malignant lesions in non-small cell lung cancer. However the presence of gene mutations in non-malignant bronchial tissue has remained controversial. The present study was carried out to investigate systematically the presence of mutations of the K-ras and p53 gene in bronchial biopsies taken during routine bronchoscopy of normal as well as tumour tissues from a series of 40 patients with histologically verified non-small cell lung cancer (NSCLC). K-ras mutations were analysed with specific detection oligonucleotides, p53 mutations were examined by SSCP analysis. In all biopsies the wildtype of both K-ras and p53 could be detected. The overall frequency of mutations was 14 (35%) with 2 K-ras mutations (5%) and 12 mutations of the p53 gene (30%). In 3 cases (1 ras mutation, 2 p53 mutations) the same mutation could be shown in the tumour biopsy and in the distant normal control. In another case only the normal appearing tissue had a mutation of the p53 gene. All other mutations could be detected in the tumour tissue only. Our data confirm that K-ras mutations and p53 can be detected not only in malignant but also in non-malignant bioptic samples from patients with NSCLC. The use of molecular screening for the early detection of lung cancer may be a promising new approach.

Adenocarcinoma↗
PubMed2000

High-dose-rate brachytherapy: dose escalation in three-dimensional miniorgans of the human bronchial wall.

PURPOSE: High-dose-rate (HDR) brachytherapy of human lung cancer is well established, however fractionation schemes and dosages are based mainly on experience. The aim of this investigation was to study the effects of different doses of HDR iridium-192 on normal human bronchial epithelium in three-dimensional miniorgans of the human bronchial wall. METHODS AND MATERIALS: Forty-eight biopsies from normal bronchi were cultivated for 14 days and exposed at random to different doses of HDR iridium 192 (0 Gy, 30 Gy, 45 Gy, 60 Gy, or 75 Gy). Cell viability was assessed immediately after irradiation, after 4 or 18 days by fluorescent staining, and cell damage of the culture was analyzed by light microscopy. Lactate dehydrogenase (LDH) was measured in the supernatant for 4 days. RESULTS: There was no histologically apparent tissue damage regardless of the irradiation dose. The number of nonvital cells increased in irradiated miniorgans depending on the dose used (p < 0. 05 at 75 Gy). This effect occurred early and was less pronounced with time. LDH measurements showed an increase only in the first 24 hours. CONCLUSIONS: Our results confirm that normal bronchial epithelium has a high tolerance to early epithelial damage by irradiation. This model of human bronchial miniorgans is useful for further studies of the effects of irradiation on human bronchi.

Brachytherapy↗
PubMed2000

Clinical manifestations of AB-amyloidosis: effects of biocompatibility and flux.

BACKGROUND: Highly permeable biocompatible dialysis membranes may postpone the development of AB-amyloidosis, but the relative contribution of enhanced flux or reduced inflammation by highly biocompatible membranes and sterile dialysis fluid remains unknown. METHODS: In this retrospective investigation, 89 patients with end-stage renal disease maintained on regular haemodialysis for at least 10 years and treated with one type of dialysis membrane exclusively were selected for analysis. They were divided into three groups: low-flux, bioincompatible cellulose (I), low-flux, intermediately biocompatible polysulphone or PMMA (II), or high-flux, highly biocompatible polysulphone or AN69 (III). In addition, the patients were analysed according to the microbiological quality of the dialysis fluid, which had been tested regularly and was classified either as standard or as intermittently contaminated. The clinical manifestations indicative of AB-amyloidosis, namely, carpal tunnel syndrome, arthropathy and bone cysts, were diagnosed after recruitment. RESULTS: Clinical symptoms were most pronounced in group I, intermediate in group II, and lowest in group III. Patients treated with intermittently contaminated dialysis fluid showed a higher prevalence of AB-amyloidosis than patients with less contaminated dialysis fluid. Logistic regression analysis demonstrated that the flux characteristics of the dialyser and the microbiological quality of the dialysis fluid as well as the biocompatibility of the dialyser were independent determinants of AB-amyloidosis. CONCLUSION: It would be prudent clinical practice to employ high-flux biocompatible membranes in conjunction with ultrapure dialysis fluid for the treatment of end-stage renal disease patients who need to remain on long-term haemodialysis.

Acrylic Resins↗
PubMed2000

Simian immunodeficiency virus containing mutations in N-terminal tyrosine residues and in the PxxP motif in Nef replicates efficiently in rhesus macaques.

SIVmac Nef contains two N-terminal tyrosines that were proposed to be part of an SH2-ligand domain and/or a tyrosine-based endocytosis signal and a putative SH3-ligand domain (P(104)xxP(107)). In the present study, we investigated the effects of combined mutations in these tyrosine and proline residues on simian immunodeficiency virus (SIV) Nef interactions with the cellular signal transduction and endocytic machinery. We found that mutation of Y(28)F, Y(39)F, P(104)A, and P(107)A (FFAA-Nef) had little effect on Nef functions such as the association with the cellular tyrosine kinase Src, downregulation of cell surface expression of CD4 and class I major histocompatibility complex, and enhancement of virion infectivity. However, mutations in the PxxP sequence reduced the ability of Nef to stimulate viral replication in primary lymphocytes. Three macaques infected with the SIVmac239 FFAA-Nef variant showed high viral loads during the acute phase of infection. Reversions in the mutated prolines were observed between 12 and 20 weeks postinfection. Importantly, reversion of A(107)-->P, which restored the ability of Nef to coprecipitate a 62-kDa phosphoprotein in in vitro kinase assays, did not precede the development of a high viral load. The Y(28)/Y(39)-->F(28)/F(39) substitutions did not revert. In conclusion, mutations in both the tyrosine residues and the putative SH3 ligand domain apparently do not disrupt major aspects of SIV Nef function in vivo.

Animals↗