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Biomedical subjects

C Witt

Publications and source records attributed to C Witt.

At least 91 records · Page 5Linked to original sources
PubMed1998

Increased secretion of pro-inflammatory cytokines by circulating polymorphonuclear neutrophils and regulation by interleukin 10 during intestinal inflammation.

BACKGROUND: Concentrations of pro-inflammatory cytokines are increased in the intestinal mucosa of patients with active inflammatory bowel disease (IBD). Polymorphonuclear neutrophil granulocytes (PMN) are the most abundant cell type in intestinal lesions in IBD. Interleukin 10 (IL-10) is an important contra-inflammatory cytokine which induces downregulation of pro-inflammatory cytokines. AIMS: To investigate whether PMN from patients with IBD or infectious colitis, respectively, secrete increased amounts of pro-inflammatory cytokines and can be regulated by IL-10. METHODS: Secretion (ELISA) as well as corresponding mRNA levels (semiquantitative RT-PCR) of pro-inflammatory cytokines (IL-1 beta, TNF-alpha) and of IL-1 receptor antagonist were assessed in peripheral PMN. RESULTS: PMN from patients with IBD are primed to secrete enhanced amounts of pro-inflammatory cytokines accompanied by detection of corresponding mRNAs in comparison with normal controls. This finding is not specific for IBD but rather reflects intestinal inflammation in general. IL-10 markedly inhibited proinflammatory cytokine secretion as well as corresponding mRNA concentrations. CONCLUSIONS: PMN are an important source of pro-inflammatory cytokines in patients with intestinal inflammation and can be downregulated by IL-10.

Adolescent↗
PubMed1998

Pituitary adenylate cyclase activating peptides relax human pulmonary arteries by opening of KATP and KCa channels.

BACKGROUND: Pituitary adenylate cyclase activating peptides (PACAPs) are potent endothelium independent dilators of human coronary arteries; however, their effects on human pulmonary arteries are unknown. METHODS: The vasorelaxant effects of PACAP27 on human pulmonary segmental arteries were studied and the specific potassium (K+) channel regulatory mechanisms in the vasorelaxant effects were tested by means of isometric contraction experiments. RESULTS: PACAP27 produced dose dependent relaxations of 10 microM rings preconstricted with prostaglandin F2 alpha (PGF2 alpha) with half maximal relaxation (IC50) at 17 nM. Pretreatment of the vessels with the ATP sensitive K+ (KATP) channel blocker glibenclamide (1 microM) or with the Ca2+ activated K+ (KCa) channel blocker iberiotoxin (100 nM) inhibited the PACAP27 induced relaxation. CONCLUSIONS: These results provide evidence that PACAPs are potent vasodilators of human pulmonary arteries and that this relaxation might be mediated by opening of KATP and KCa channels.

Analysis of Variance↗
PubMed1998

[Endoscopic interventions in the tracheobronchial system].

Therapeutic bronchoscopy is widely used in the treatment of airway stenosis, fistula, and pulmonary bleeding. Recanalisation of tracheobronchial stenoses can be treated by Nd: YAG-laser or stent implantation. While the use of laser irradiation is limited to intraluminal obstruction, stenting is also effective in stenoses due to extraluminal compression. Stent implantation has also become the method of choice in the treatment of tracheobronchial fistulas. A more specific strategy in the treatment of malignant lesions is photodynamic therapy. By use of photosensitizers and subsequent irradiation tumor cells can be destroyed selectively. Gene therapy represents a promising new approach in tumor therapy. After retrovirus-mediated gene transfer of a suppressor gene an increase of tumor cell apoptosis was observed. Altogether interventional pneumology has experienced substantial enlargement of therapeutic possibilities.

Bronchial Diseases↗
PubMed1998

Cyanotic heart lesions with increased pulmonary blood flow.

This article examines common cyanotic congenital heart lesions that result in an increase in pulmonary blood flow. These lesions include transposition of the great arteries, truncus arteriosus, total anomalous pulmonary venous connection, tricuspid atresia, and single ventricle. The complications caused by increased pulmonary blood flow are examined. The hemodynamics, presentation, diagnosis, medical management, and surgical treatment of each lesion are discussed. Support and teaching needs of the parents are also addressed.

Heart Defects, Congenital↗
PubMed1997

Deletion in the Z-line region of the titin gene in a baby hamster kidney cell line, BHK-21-Bi.

The gene for titin, a 4MDa myofibrillar protein, was analysed in golden hamster DNAs from different sources, using human cDNA probes and PCR. In the DNA from the BHK-21-Bi subline of baby hamster kidney cells, extended sequences coding for Z-line associated domains were missing, indicating a deletion that renders titin non-functional. These sequences were present in the original BHK-21 line and in hamster DNAs. Our finding shows that, due to the absence of selective pressure on a gene's function, genomic deterioration can occur in a permanent cell line and can lead to a loss of overlapping DNA stretches in both autosomes.

Animals↗
PubMed1997

Human airway smooth muscle cells express and release RANTES in response to T helper 1 cytokines: regulation by T helper 2 cytokines and corticosteroids.

RANTES is a basic 8-kDa polypeptide of the C-C chemokine subfamily with strong chemotactic activity for eosinophils, lymphocytes, and monocytes. We determined the regulation of RANTES production by human airway smooth muscle cells in culture. While TNF-alpha, but not IFN-gamma, increased RANTES mRNA expression and protein release, the combination of TNF-alpha and IFN-gamma caused a greater degree of expression and release in a time- and dose-dependent manner. Sequential treatment of airway smooth muscle cells with TNF-alpha and IFN-gamma showed that IFN-gamma sensitized the cells to the stimulatory effect of TNF-alpha. Using a modified Boyden chamber technique, RANTES separated by reverse-phase liquid chromatography from cell culture supernatants of airway smooth muscle cells stimulated by TNF-alpha and IFN-gamma showed a strong chemoattractant effect on human eosinophils, an effect inhibited by an anti-RANTES Ab. RANTES production induced by TNF-alpha and IFN-gamma was inhibited partly by the Th2-derived cytokines, IL-4, IL-10, and IL-13, as well as by dexamethasone. Our studies indicate that, in addition to contractile responses and mitogenesis, airway smooth muscle cells have synthetic and secretory potential with the release of RANTES. They may participate in chronic airway inflammation by interacting with both Th1- and Th2-derived cytokines to modulate chemoattractant activity for eosinophils, activated T lymphocytes, and monocytes/macrophages.

Adrenal Cortex Hormones↗
PubMed1997

Nd:YAG laser and tracheobronchial metallic stents: an experimental in vitro study.

STUDY DESIGN/MATERIALS AND METHODS: The aim of this experimental study was to investigate the effect of Nd:YAG laser on metallic tracheobronchial stents, because Nd:YAG laser could be used for resection of tumourous tissue growing through stent meshes (Strecker-, Palmaz-, Wallstent). STUDY DESIGN/MATERIALS AND METHODS: An in vitro worst-case-model was used to investigate the effects of different types of laser application on metallic stents: non-contact application, and contact application with bare fibres and with hemispherical sapphires. RESULTS: In the non-contact method and with bare fibres stent destruction occurred at power settings exceeding 10 W, whereas in the contact method with hemispherical sapphires power settings of 20 W were possible without stent damage.

Animals↗
PubMed1997

Acute right-sided heart failure due to hemorrhage into a pericardial cyst.

This is a description of a rare complication of a pericardial cyst with spontaneous internal hemorrhage and following tamponade. The noninvasive diagnosis was done by transesophageal echocardiography and computed thoracic tomography. The cyst was thoracoscopically removed and pathologically examined. This case demonstrates a rare but important and life-threatening complication of mostly asymptomatic pericardial cysts.

Acute Disease↗
PubMed1997

Radiographic manifestations of multiple myeloma in the mandible: a retrospective study of 77 patients.

PURPOSE: This retrospective study was done to determine the frequency and radiographic pattern multiple myeloma in the mandible. PATIENTS AND METHODS: Seventy-seven patients with multiple myeloma were studied using skull and panoramic radiographs of the jaws made at the time of initial diagnosis. RESULTS: Skull manifestations were present in 46.7% and jaw manifestations in 15.6% of the cases studied. The pattern of jaw involvement was characterized by osteolytic lesions without other radiographic manifestations of bone involvement. There was no relationship between the pattern of jaw and extragnathic involvement and increased M-component of secreted immune globulin. Jaw involvement was largely unaccompained by oral symptoms. CONCLUSION: The results suggest that mandibular lesions are a common finding in multiple myeloma.

Adult↗
PubMed1997

Temporary tracheobronchial stenting in malignant stenoses.

Endobronchial stent implantation has been successfully employed in malignant stenoses. The aim of this prospective study was to investigate the temporary use of tracheobronchial stents combined with tumour-specific therapy. All patients received stents for primary palliation of dyspnoea followed by radio- or chemotherapy with the aim of stent removal after reduction of the stenosis. In 22 patients suffering from severe malignant strictures, 34 endobronchial stents (29 Strecker-, 3 Dumon-, 1 Orlowski-, 1 Dynamic-Y-stents) were implanted (in 9 patients, 2 stents were necessary). Patients were treated by irradiation (n = 18) or chemotherapy (n = 4) after stent implantation. Significant improvement of dyspnoea (P < 0.001) and partial oxygen pressure (P < 0.01) was observed. In 11 out of 22 cases (50%), the stents could be removed after successful tumour-specific therapy which led to reduction of stenosis after a mean interval of 31.7 (6-104) days (temporary stenting). During the period of tumour-specific therapy, 9 patients died after a mean interval of 132 (13-347) days (definite stenting). In two cases, stents had to be removed after stent compression, stent dislocation and severe cough. The results suggest that temporary stenting, characterised by subsequent successful tumour-specific therapy, is a new valuable therapeutic strategy. It can "bridge the gap" before tumour-specific therapy can take effect. If tumour-specific therapy is ineffective, definite stenting is the palliative method of choice in severe dyspnoea in bronchial carcinoma.

Adult↗
PubMed1997

Arousals and sleep stages in patients with obstructive sleep apnoea syndrome: Changes under nCPAP treatment.

Nocturnal arousals are the essential cause of disturbed sleep structure in patients with obstructive sleep apnoea syndrome (OSAS). The aim of this study was to analyse the relationship between sleep stages, respiratory (type-R) and movement (type-M) related EEG arousals. Furthermore, the value of these arousals as a criterion for the efficiency of nCPAP treatment was estimated. We examined 38 male patients aged between 30 and 71 (49.1 +/- 20.9 SD) y. All patients suffered from OSAS. The mean respiratory disturbance index (RDI) was 47.3 +/- 27.8 per h. Polysomnographic monitoring was carried out on 4 subsequent nights: baseline night, 2 nights of nCPAP titration and nCPAP control night. Sleep was visually scored and EEG arousals were classified into type R and M, depending on whether changes of respiration or movement caused the arousal. The RDI, the R index (type-R/h), the M index (type-M/h) and the R and M indices in different sleep stages were calculated. During the baseline night a deficit of slow wave sleep (SWS) and REM sleep was found. Furthermore there were more type-R than type-M arousals registered (17.4 h-1 [3.6-43.6] vs. 5.9 h-1 [1.6-11.8]) (P < 0.01). They occurred during stages NREM 1, NREM 2 and REM (P < 0.01). An SWS sleep rebound and a reduction of the SWS and REM latencies were already found during the first CPAP night. The R index was reduced during the first CPAP night in all sleep stages (P < 0.01) and remained approximately the same in the following 2 nights (3. CPAP night: 1.1 h-1 [0.3-5.0]). Type M arousals occurred more in stages 1 and 2 (P < 0.01), and remained unchanged under nCPAP. We concluded that differentiation of nocturnal arousals may provide more detailed information regarding the influence of breathing disturbances on sleep. Respiratory related, not movement related, arousals may be a useful additional tool in judging the efficiency of OSAS.

Adult↗
PubMed1997

Respiratory muscle weakness and normal ventilatory drive in dilative cardiomyopathy.

BACKGROUND: In dilative cardiomyopathy several factors influence dyspnoea. Patients with chronic heart failure may demonstrate impairment of breathing pattern, ventilatory drive and respiratory muscle strength, as well as reduction of ventilatory efficiency. The purpose of this study was to evaluate whether dilative cardiomyopathy is accompanied by changes in breathing pattern, respiratory muscle weakness and ventilatory neural drive. METHODS: We investigated 47 patients (36 men, mean age = 47.8 +/- 11.2 years) with chronic heart failure due to dilative cardiomyopathy, and 30 healthy subjects (10 men, mean age = 35.4 +/- 11.7 years) served as controls. Patients and controls underwent evaluation of left ventricular ejection fraction by 2D echocardiography, spirometry, body plethysmography, mouth occlusion pressure and respiratory muscle strength, as well as by submaximal treadmill exercise testing with gas exchange measurements. The patients' results were compared to controls and predicted standard normal values, and evaluated for differences according to the degree of severity of functional impairment. RESULTS: Patients with dilative cardiomyopathy demonstrated a slight reduction in lung volumes (15% of the patients with obstructive and 15% with restrictive lung function pattern) and diffusion capacity (20.4 +/- 6.8 vs 15.4 +/- 6.7 ml.min-1.kPa-1; P < 0.01). In neural drive, as assessed by mouth occlusion pressure, there was no significant difference between patients and controls. There was a slight but significant reduction in respiratory muscle strength, as assessed by measuring maximal inspiratory pressure in patients with dilative cardiomyopathy (6.7 +/- 2.4 kPa vs 8.6 +/- 3.5 kPa; P < 0.01). The observed changes were more pronounced in the severe chronic heart failure patients (with a reduction in ventilatory efficiency) whereas no relationship among indices of cardiac or respiratory function was found. CONCLUSIONS: Patients with chronic heart failure due to dilative cardiomyopathy develop respiratory muscle weakness without changes in neural ventilatory drive, and slight changes in breathing pattern related to the severity of the disease.

Adult↗
PubMed1997

Cytokines derived from alveolar macrophages induce fever after bronchoscopy and bronchoalveolar lavage.

As much as one-third of patients develop fever and flu-like symptoms after fiberoptic bronchoscopy (FOB) and bronchoalveolar lavage (BAL) for yet unknown reasons. The aim of the present study was to investigate factors mediating these side effects. Fifty consecutive patients with various pulmonary diseases who underwent FOB without further interventions (n = 30) or combined with BAL (n = 20) were enrolled. Serum levels of the proinflammatory cytokines IL-1beta, IL-6, and TNF-alpha were determined directly prior to (t0), directly after (t1), and 6 h after (t2) the procedures by ELISA. In parallel, blood cultures were drawn at t2. At to and t1, generally only low cytokine concentrations could be detected. At t2, however, significant increases of cytokine levels were found. IL-6 and TNF-alpha were significantly higher in patients after BAL than in patients after FOB. Comparing patients who developed fever (n = 12) with those who did not (n = 38), irrespective of the endoscopic procedures performed, dramatic increases of all three cytokines were detected in febrile patients that were significantly higher than in patients without fever. In the FOB group only patients who received local anesthesia by prilocaine bolus injection into the airways via the working channel of the bronchoscope developed fever and increases of IL-6 and IL-beta, whereas patients anaesthetized by inhalation of a prilocaine aerosol remained afebrile and had slight IL-6 increases only. There was a highly significant correlation between IL-6 values at t2 and the number of BAL alveolar macrophages (r = 0.98). All blood cultures remained sterile. These results indicate that fever after FOB and BAL is induced by proinflammatory cytokines derived from alveolar macrophages activated by instillation of fluid into the airways.

Adult↗
PubMed1997

Effect of frequency altered feedback and audience size on stuttering.

The effect of frequency altered feedback (FAF) and audience size on stuttering frequency was examined. Nine adults who stutter orally read to audiences of two, four and 15 people under conditions of FAF (one-half octave shift down) and non-altered auditory feedback (NAF). There was no statistically significant effect of audience size on stuttering frequency (p > 0.05). A statistically significant reduction in stuttering frequency was found under FAF relative to NAF (p < 0.5). Collapsed across audience conditions, stuttering frequency was reduced by 74%. These findings suggest that FAF may be useful as a treatment tool.

Adult↗
PubMed1997

Severe prosthetic valve-related endocarditis following dental scaling: a case report.

There is a well-known correlation between surgical dental procedures and the risk of bacterial endocarditis in patients with prosthetic cardiac valves. A 43-year-old patient with prosthetic aortic and mitral valves, which already have been removed twice because of endocarditis, suffered from a prosthetic valve-related endocarditis following dental scaling, which was performed without any antibiotic prophylaxis. Invasive medical procedures in patients with prosthetic heart valves may lead to endocarditis. Antibiotic prophylaxis is recommended even for dental procedures considered to be "harmless," such as dental scaling.

Adult↗
PubMed1997

[Stent implantation in severe tracheal and bronchial compression caused by aortic aneurysm].

A space-occupying growth in the left upper area of the lung was confirmed in a female patient of 75 years of age suffering from progressive cough and intermittent dyspnoea. Fibre bronchoscopy revealed distal stenosis of the trachea, the total findings being interpreted as pointing to the existence of a mediastinal tumour. A few hours after bronchoscopy the patient suffered from respiratory insufficiency, and the patient was referred to us with continuously increasing positive airway pressure breathing, for further clarification. We performed as an emergency measure bilaterally an endobronchial stent implantation. After airway pressure breathing had returned to normal, and subsequent extubation, compression of a stent occurred followed by renewed compulsory breathing. Ventilation could be optimised by an additional implantation of a stent. Cause of the compression was later identified as a monstrous aneurysm of the thoracic and abdominal aorta. During further conservative treatment there was a progressive bronchopneumonia and renal insufficiency requiring dialysis. The patient died on the 8th day after stent implantation. Autopsy showed that the stents were properly in position.

Aged↗
PubMed1997

Cardiac embryology.

The cardiovascular system is the first major organ system to develop in the embryo, being fully formed and functioning by the eighth week of gestation. This early, rapid development may explain the prevalence of congenital heart disease. Infants with congenital heart disease require considerable nursing skill and an understanding of the particular diagnosis. Nurses who understand basic cardiac embryology will better understand the various defects, how they occur, and how they affect cardiac physiology and functioning. This article discusses development of the heart and major vessels arising from the heart and relates stages of development to corresponding congenital heart defects.

Heart↗