Biomedical subjects

J Gade

Publications and source records attributed to J Gade.

At least 19 recordsLinked to original sources

PubMed2001

Bronchial transsection and reanastomosis in pigs with and without bronchial arterial circulation.

BACKGROUND: The bronchial artery may be vital to the bronchi and lung parenchyma, but results of lung transplantation have raised doubts. This study was performed to examine the effect of bronchial arterial devascularization on bronchial morphology after bronchial transsection and reanastomosis. METHODS: In 6 pigs (study group), the left main bronchus was transsected, reanastomosed, and devascularized. Six control pigs had the same operation without devascularization. After 1 week, bronchial arterial angiography was performed, and specimens were examined with conventional histology and scanning electron microscopy. RESULTS: Histology showed significant changes (inflammation, edema, and fibrosis) in bronchi and lung parenchyma of the study group compared with the unoperated side (p = 0.028) and with the control group (p = 0.050). Scanning electron microscopy showed significant ciliary denudation in the study group's left bronchus compared with the unoperated side (p = 0.043) and with the control group (p = 0.0071). CONCLUSIONS: The loss of cilia of the bronchial epithelium and the occurrence of inflammation, edema, and fibrosis in bronchi and lung parenchyma 1 week postoperatively were significantly related to the absence of the bronchial arterial circulation.

Anastomosis, Surgical↗

PubMed2001

Bronchial arterial devascularization. An experimental study in pigs.

OBJECTIVE: The lungs have dual blood supply: The bronchial and the pulmonary circulation. The importance of bronchial circulation is disputed. The purpose of this study was to establish an experimental model to examine the importance of the bronchial artery. DESIGN: Comparative porcine experimental study. The surgical technique was evaluated in group A (n = 9). Group B (n = 8) underwent left bronchial arterial devascularization. In group C (n = 9) the left principal bronchus was devascularized, transsected, and reanastomosed. In groups B and C bronchial mucosal blood flow was studied with laser-Doppler velocimetry. Devascularization was controlled by angiography at section, and specimens were examined with conventional histology and scanning electron microscopy. The right bronchus served as control. RESULTS: In group B devascularization caused considerable, yet insignificant reduction in bronchial mucosal blood flow index (p = 0.1282) postoperatively, and after 1 week (p = 0.0678), insignificant histologic (p > 0.2) changes, and no scanning electron microscopy differences. In group C devascularization with bronchial transsection caused significant reduction in mucosal blood flow index (p = 0.0277) postoperatively and after 1 week (p = 0.0277), significant histologic changes (p = 0.0277), and insignificant (p = 0.069) changes in scanning electron microscopy. CONCLUSION: Bronchial arterial devascularization with transsection caused significant physiologic and morphologic changes, and a model with bronchial devascularization should include transsection.

Angiography↗

PubMed2000

Technical description of the IBIS data library. Improved Monitoring for Brain Dysfunction in Intensive Care and Surgery.

The IBIS Data Library (DL) is an annotated data library that contains practically all the monitored data and other clinical information from critically ill patients during surgery and in intensive care. The data have been collected at three sites: the intensive care unit of the Kuopio University Hospital, Finland; Royal Brompton Hospital, London, UK; and St. Bartholomew's Hospital, London, UK. The purpose of the DL is to form the basis for development of biosignal interpretation methods in the Improved Monitoring for Brain Dysfunction in Intensive Care and Surgery project in the European Union (EU) BIOMED2 programme (BMH4-97-2570). The DL contains continuous electroencephalography signals, multimodal evoked potential recordings and diagnostic electrocardiography recorded during intensive care and surgery. In addition, signal types similar to those recorded during an earlier project, the EU-BIOMED1 project IMPROVE, are stored in the DL. In addition, trend data from patient monitors, laboratory data, annotations, nursing actions, and medications recorded and stored by a Patient Data Management System (PDMS) during routine care are included. The data obtained routinely are complemented by special annotations made by a physician who observes the patient during the data collection session. Annotations include, for example, assessment of the awareness of the patient and specific events during surgery not recorded routinely by the PDMS. Inclusion of information about the care plan and the aims of the care make the contents of the DL complete. The present paper describes the technical set-up used for recording of the DL and the contents of the DL. The paper also includes an appendix defining a new data format, the extended evoked potentials format, used for storage of sweep data in the DL.

Brain↗

PubMed2000

Glucose uptake is increased in trained vs. untrained muscle during heavy exercise.

Endurance training increases muscle content of glucose transporter proteins (GLUT-4) but decreases glucose utilization during exercise at a given absolute submaximal intensity. We hypothesized that glucose uptake might be higher in trained vs. untrained muscle during heavy exercise in the glycogen-depleted state. Eight untrained subjects endurance trained one thigh for 3 wk using a knee-extensor ergometer. The subjects then performed two-legged glycogen-depleting exercise and consumed a carbohydrate-free meal thereafter to keep muscle glycogen concentration low. The next morning, subjects performed dynamic knee extensions with both thighs simultaneously at 60, 80, and until exhaustion at 100% of each thigh's peak workload. Glucose uptake was similar in both thighs during exercise at 60% of thigh peak workload. At the end of 80 and at 100% of peak workload, glucose uptake was on average 33 and 22% higher, respectively, in trained compared with untrained muscle (P < 0.05). Training increased the muscle content of GLUT-4 by 66% (P < 0. 05). At exhaustion, glucose extraction correlated significantly (r = 0.61) with total muscle GLUT-4 protein. Thus, when working at a high load with low glycogen concentrations, muscle glucose uptake is significantly higher in trained than in untrained muscle. This may be due to the higher GLUT-4 protein concentration in trained muscle.

Adaptation, Physiological↗

PubMed1999

Two evolutionarily closely related ABC transporters mediate the uptake of choline for synthesis of the osmoprotectant glycine betaine in Bacillus subtilis.

Biosynthesis of the compatible solute glycine betaine in Bacillus subtilis confers a considerable degree of osmotic tolerance and proceeds via a two-step oxidation process of choline, with glycine betaine aldehyde as the intermediate. We have exploited the sensitivity of B. subtilis strains defective in glycine betaine production against glycine betaine aldehyde to select for mutants resistant to this toxic intermediate. These strains were also defective in choline uptake, and genetic analysis proved that two mutations affecting different genetic loci (opuB and opuC) were required for these phenotypes. Molecular analysis allowed us to demonstrate that the opuB and opuC operons each encode a binding protein-dependent ABC transport system that consists of four components. The presumed binding proteins of both ABC transporters were shown to be lipoproteins. Kinetic analysis of [14C]-choline uptake via OpuB (K(m) = 1 microM; Vmax = 21 nmol min-1 mg-1 protein) and OpuC (K(m) = 38 microM; Vmax = 75 nmol min-1 mg-1 protein) revealed that each of these ABC transporters exhibits high affinity and substantial transport capacity. Western blotting experiments with a polyclonal antiserum cross-reacting with the presumed substrate-binding proteins from both the OpuB and OpuC transporter suggested that the expression of the opuB and opuC operons is regulated in response to increasing osmolality of the growth medium. Primer extension analysis confirmed the osmotic control of opuB and allowed the identification of the promoter of this operon. The opuB and opuC operons are located close to each other on the B. subtilis chromosome, and their high sequence identity strongly suggests that these systems have evolved from a duplication event of a primordial gene cluster. Despite the close relatedness of OpuB and OpuC, these systems exhibit a striking difference in substrate specificity for osmoprotectants that would not have been predicted readily for such closely related ABC transporters.

ATP-Binding Cassette Transporters↗

PubMed1999

The porcine bronchial artery: surgical and angiographic anatomy.

The pig is often used in experimental studies on the significance of bronchial artery circulation, but the anatomy of this artery is only poorly described. The purpose of this study was to improve the anatomical basis for experimental studies on the porcine bronchial artery circulation. The origin of the artery from the aorta is described in 32 pigs. Heart-lung blocks were perfused with saline and removed in 16 pigs, and the broncho-oesophageal orifice was identified and cannulated. In these 16 specimens the intrapulmonary ramification was studied by angiography, and the extrapulmonary distribution and supply area by injection of Evans Blue. The broncho-oesophageal artery originated from the aorta as a single trunk in 91%. Angiography showed that each principal bronchus was accompanied by 2 bronchial artery branches far into the lung parenchyma. The central branching pattern of the artery between the aorta and the principal bronchi was divided into 3 subtypes. Evans Blue showed communication with the whole mediastinum. The anatomical relations are described. It is concluded that the broncho-oesophageal artery divides to follow each bronchus with 2 bronchial branches. A nomenclature for these branches is suggested. The pig anatomy is suited for experimental investigations on the bronchial circulation.

Animals↗

PubMed1999

The porcine bronchial artery. Anastomoses with oesophageal, coronary and intercostal arteries.

Information about the existence and anatomy of arterial anastomoses with the porcine bronchial artery is lacking in the literature. Prior to basic physiological investigations in a porcine model related to lung transplantation with bronchial artery revascularisation, this study was designed to examine the anatomy of systemic arterial anastomoses with the bronchial artery system. Twenty pigs were studied in 3 groups. In 2 groups the heart-lung block was removed with all mediastinal structures. One group served for investigation of coronary-bronchial artery anastomoses and one for investigation of oesophageal-bronchial artery anastomoses. The systemic arteries to be examined were cannulated. The inflated heart-lung block was examined macroscopically with Evans blue, and radiographically after contrast injection. In the 3rd group intercostobronchial artery anastomoses were studied radiographically with the heart-lung block in situ. Coronary-bronchial artery anastomoses were demonstrated in 3 of the 5 pigs with an aortic 'pouch' technique, but contrast was very limited in 2 of these 3. Oesophageal arterial anastomoses with bronchial arterial branches and/or the pulmonary veins were demonstrated in 6 of the 7 pigs and more markedly than the coronary-bronchial anastomoses. Intercostobronchial artery anastomoses could not be demonstrated angiographically. It was concluded that the existence of coronary-bronchial and oesophageal-bronchial artery anastomoses in the pig appear to establish an arterial net between the base of the heart and the distal oesophagus. The resemblance to human oesophageal-bronchial artery anastomoses supports use of a porcine model for experimental studies.

Animals↗

PubMed1998

Digital archival and exchange of events in a simple format for polygraphic recordings with application in event related potential studies.

This paper describes a simple method of event encoding as an extension to a previously defined standard format, the European Data Format (EDF). The specification ensures full backward compatibility with the existing definition. By using this extension, the format can be used to store both continuous recordings and selected epochs of recordings. The encoding is performed in a channel of event-codes or in a pseudo-channel for annotations. Standardisation of event encoding is discussed. Decoding of events or annotations from the extended format is implemented at the application level. Existing programs that do not support the new encoding scheme still operate correctly and can simply ignore the new channels in processing 'extended' data files. The event encoding is also compatible with EDF's capability to encode channels of different sampling frequency.

Data Interpretation, Statistical↗

PubMed1998

Physicians' abdominal auscultation. A multi-rater agreement study.

BACKGROUND: Abdominal auscultation has an important position in the physical examination of the abdomen. Little is known about rater agreement. The aim of this study was to describe rater agreement and thus, indirectly, the value of the examination. METHODS: In a semi-virtual setup 12 recordings of the intestinal sounds from 8 patients with acute abdominal pain and 4 healthy volunteers were presented to 100 physicians. The physicians were asked to characterize the intestinal sounds as normal or pathologic. Fisher's exact test was used for comparison between groups of physicians. RESULTS: Overall, 72% of the answers with regard to healthy volunteers concluded that the sounds were normal (equalling agreement), whereas 64% of answers with regard to intestinal obstruction concluded that the sounds were pathologic (but agreement was higher due to agreement on wrong diagnosis in one case). Bowel sounds from colonic obstruction were diagnosed as pathologic in 94 of 100 answers. In peritonitis disagreement dominated. Specialists in gastrointestinal medicine diagnosed bowel obstruction significantly more poorly than non-specialists in gastrointestinal surgery (P < 0.05). CONCLUSION: Rater agreement in normal subjects and in patients with intestinal obstruction was acceptable for a clinical examination. Abdominal auscultation is a helpful clinical examination in patients with acute abdominal pain.

Abdomen↗

PubMed1997

Lipoprotein from the osmoregulated ABC transport system OpuA of Bacillus subtilis: purification of the glycine betaine binding protein and characterization of a functional lipidless mutant.

The OpuA transport system of Bacillus subtilis functions as a high-affinity uptake system for the osmoprotectant glycine betaine. It is a member of the ABC transporter superfamily and consists of an ATPase (OpuAA), an integral membrane protein (OpuAB), and a hydrophilic polypeptide (OpuAC) that shows the signature sequence of lipoproteins (B. Kempf and E. Bremer, J. Biol. Chem. 270:16701-16713, 1995). The OpuAC protein might thus serve as an extracellular substrate binding protein anchored in the cytoplasmic membrane via a lipid modification at an amino-terminal cysteine residue. A malE-opuAC hybrid gene was constructed and used to purify a lipidless OpuAC protein. The purified protein bound radiolabeled glycine betaine avidly and exhibited a KD of 6 microM for this ligand, demonstrating that OpuAC indeed functions as the substrate binding protein for the B. subtilis OpuA system. We have selectively expressed the opuAC gene under T7 phi10 control in Escherichia coli and have demonstrated through its metabolic labeling with [3H]palmitic acid that OpuAC is a lipoprotein. A mutant expressing an OpuAC protein in which the amino-terminal cysteine residue was changed to an alanine (OpuAC-3) was constructed by oligonucleotide site-directed mutagenesis. The OpuAC-3 protein was not acylated by [3H]palmitic acid, and part of it was secreted into the periplasmic space of E. coli, where it could be released from the cells by cold osmotic shock. The opuAC-3 mutation was recombined into an otherwise wild-type opuA operon in the chromosome of B. subtilis. Unexpectedly, this mutant OpuAC system still functioned efficiently for glycine betaine acquisition in vivo under high-osmolarity growth conditions. In addition, the mutant OpuA transporter exhibited kinetic parameters similar to that of the wild-type system. Our data suggest that the lipidless OpuAC-3 protein is held in the cytoplasmic membrane of B. subtilis via its uncleaved hydrophobic signal peptide.

ATP-Binding Cassette Transporters↗

PubMed1996

Modelling techniques and their application for monitoring in high dependency environments--learning models.

This paper reviews the use of learning models including Bayesian classifiers and artificial neural networks in monitoring and interpreting biosignals. Generally learning models applied for analysis of biosignals are "black-box' types trained on the basis of measured signals. It is illustrated that the training and application of learning models more or less follow the same sequences. The main focus is the interpretation of electrical signals from the brain (electroencephalogram (EEG) and evoked potentials (EP)). Current analysis of these signals often reveals sudden changes in the EEG or evoked potentials to be the earliest discernible signs of inadequate perfusion of the brain. They may reflect problems such as systemic arterial oxygen desaturation or hypotension arising from other body system failures during critical illness. It is suggested that these brain signals should be recorded in the critical care unit, and that they should form part of the annotated database of biosignals established during the IMPROVE project. This would allow for the development of new methods for on-line warning of impending damage to the central nervous system, such that corrective actions could be taken before permanent damage occurred.

Auscultation↗

PubMed1995

Sleep intensity in fibromyalgia: focus on the microstructure of the sleep process.

Alpha electroencephalography (EEG) predominance has been described during sleep in patients suffering from the fibromyalgia syndrome (FMS). However, EEG power density in the lower frequency bands probably better reflects the restorative functions of sleep. This study was conducted to describe the energy in all frequency bands in the sleep EEG. Ambulatory sleep recordings were performed on 12 women with FMS and 14 control women. Epochs were classified according to standard criteria. Moreover, all 2-s segments (n = 287,355) of the EEG in non-rapid-eye-movement (NREM) 2-4 sleep were subjected to frequency analysis using autoregressive modelling. Frequency bands were: delta (0.5-3.5 Hz), theta (3.5-8 Hz), alpha (8-12 Hz), sigma (12-14.5 Hz) and beta (14.5-25 Hz). In patients with FMS, there was a predominance of EEG power in the higher frequency bands [two-way analysis of variance (ANOVA), alpha: P = 0.043; sigma: P = 0.004] at the expense of the lower frequencies (ANOVA, delta: P = 0.005; theta: P = 0.008). The same trends were obtained for the individual sleep cycles. The calculations of total delta power in the time domain showed an exponentially declining curve in healthy subjects, but a flatter decline in FMS. The decreased power in the low-frequency range might reflect a disorder in homoeostatic and circadian mechanisms during sleep and may contribute to daytime symptoms in patients with fibromyalgia.

Adult↗

PubMed1995

The upper arm arterio-venous fistula--an alternative for vascular access in haemodialysis.

Forty-eight consecutive arteriovenous fistulae of the upper arm constructed in 44 patients between 1983 and 1987 were reviewed. The median observation time was 8.5 months (range 1 day-65 months). The overall patency rate for fistulae used for haemodialysis (early failures excluded) was 50% after one year and 38% after two years. However, only six (18.7%) of the used fistulae stopped because of thrombosis. The total number of thromboses was nine (19.6%). The main cause of discontinuance of fistulae was a high number of deaths (n = 22), presumably a result of a high median age of 62 years. Early failure rate was seven of 46 (15.2%); in three cases (6.5%) this was caused by thrombosis. The results are compared to other alternatives for radiocephalic fistulae and the difficulties of comparisons are discussed. It is concluded that the upper arm arteriovenous fistula can serve as a second choice, when a radio-cephalic fistula fails.

Adolescent↗

PubMed1995

The treatment of ureteric calculi before and after the introduction of extracorporeal shockwave lithotripsy.

Indications and treatment results of ureteric calculi one year before and one year after the introduction of ESWL were analysed in 169 consecutive patients. Sex, age, former stone operation, stone localisation and stone size were not significantly different in the two groups. Before ESW1 47% of the patients received treatment against 54% after the introduction (p > 0.3). There was no tendency towards treatment of smaller calculi. Expectedly, the number of endoscopies and ureterolithotomies was significantly reduced (p < 0.05). The treatment period (from first contact till final control) was longer with ESWL, but not significantly. Judged from the length of the hospital stay there was no major economic benefit from ESWL. In conclusion, ESWL with a second generation lithotriptor is suitable for in situ treatment of ureteric calculi. It should be first choice for ureteric calculi.

Adult↗

PubMed1995

Multi-centre comparison of five eye movement detection algorithms.

Although various investigators have suggested algorithms for the automatic detection of eye movements during sleep, objective comparisons of the proposed methods have previously been difficult due to different recording arrangements of different investigators. In this study the results of five eye movement detection algorithms applied to the same data were compared to visually scored data. The percentages of true and false detections are given for various threshold levels in rapid and slow eye movement detections. The methods gave best results when they were used with the same electrode montage they were designed for but the performance decreased when other montages were used. Subtracting the cross-talk of EEG delta activity improved the correctness of eye movement detections.

Journal Article↗

PubMed1994

Pleurodesis with polidocanol in pigs. An experimental study.

Polidocanol was instilled in five pleural cavities of three pigs. Adhesions formed in all. Adhesion distribution varied from covering a minor part to most of the lung, depending on the amount of polidocanol. One control cavity treated with sodium chloride was unaffected. Microscopy showed fibrous bridges between the pleural layers and mild submesothelial fibrosis and inflammation.

Animals↗

PubMed1994

Detection of EEG patterns related to nocturnal hypoglycemia.

The aim of the project was to detect specific EEG patterns related to hypoglycemia. EEG analysis was performed using a probabilistic classifier and unsupervised learning for the construction of learning sets for the classifier. Unsupervised learning and additional tools were used in the search for EEG patterns occurring when the blood-glucose level was below the hypoglycemic threshold. The rate of these specific EEG patterns was below 5% in normal nights. In patients who were known to have no or a reduced glucagon response to hypoglycemia, the rate increased to 20-80%.

Adult↗

PubMed1992

Cognitive function in type 1 (insulin-dependent) diabetic patients after nocturnal hypoglycaemia.

UNLABELLED: Eight Type 1 (insulin-dependent) diabetic patients with no diabetic complications were studied on two consecutive and one subsequent overnight occasions. The aim was to evaluate the influence of nocturnal hypoglycaemia on neuropsychological and reaction time tests the following morning. Hypoglycaemia was induced by i.v. insulin infusion, blood glucose nadir was 1.5 +/- 0.3 mmol/l. Duration of hypoglycaemia (blood glucose less than 3 mmol/l) was 101 +/- 38 min. Whole night sleep statistics for all patients showed no statistical differences between the normoglycaemic and hypoglycaemic nights, however, there was a tendency of prolongation of the second sleep cycle in the nights with hypoglycaemia. Each patient was used as his own control and periods with blood glucose concentration less than 3 mmol/l were compared to exactly the same periods in nights with blood glucose level over 5 mmol/l. During hypoglycaemia the amount of deep sleep was reduced and replaced by superficial sleep and arousals of short duration. Further, the reduction in deep sleep was replaced later at night. Neuropsychological test scores and reaction time measurements in the morning showed no differences between the normoglycaemic and hypoglycaemic nights. IN CONCLUSION: despite sleep disturbances, nocturnal hypoglycaemia did not impair cognitive function the following morning in Type 1 (insulin-dependent) diabetic patients.

Adult↗