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Biomedical subjects

W G Daniel

Publications and source records attributed to W G Daniel.

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

Involvement of tyrosine kinases, Ca2+ and PKC in activation of mitogen-activated protein (MAP) kinase in human polymorphonuclear neutrophils.

1. Activation of mitogen-activated protein (MAP) kinase is an early response to a wide variety of stimuli and plays an important role in the regulation of cellular functions. In the present study we investigated the activation of MAP kinase in human polymorphonuclear neutrophils (PMNs). 2. Activity of MAP kinase and protein kinase C (PKC) was measured radiometrically from the rate of phosphorylation of specific peptide substrates. Protein phosphorylation was measured by immunoprecipitation and Western blot analysis. 3. N-Formyl-Met-Leu-Phe (fMLP), phorbol 12-myristate, 13-acetate (PMA) and the Ca2+-ATPase inhibitors thapsigargin (Tg) and cyclopiazonic acid (CPA) increased MAP kinase activity significantly. The tyrosine kinase inhibitors erbstatin and herbimycin A partially inhibited the effects of fMLP and PMA, and completely abolished the effects of both Tg and CPA. The specific PKC inhibitor calphostin C suppressed activation of MAP kinase produced by fMLP and PMA, but had no effect on that produced by Tg and CPA. Tg and CPA were without effect on PKC activity. 4. Immunoprecipitation and Western blot analysis indicated that the 42 and 44 kDa tyrosine-phosphorylated proteins found after stimulation of PMNs were both members of the MAP kinase family. Pretreatment of PMNs with staurosporine, EGTA or erbstatin significantly reduced the tyrosine phosphorylation of MAP kinase(s). 5. These results suggest that in human PMNs, MAP kinase can be stimulated in both a PKC-dependent and a PKC-independent manner. The Ca2+ signal leads to activation of tyrosine kinases, which contribute to the activation of MAP kinase. However, a PMA-sensitive Ca2+-independent pathway also exists. Mobilization of Ca2+ and activation of PKC synergistically induce maximal MAP kinase activation and tyrosine phosphorylation.

Calcium↗
PubMed1998

[Heart operations for heart tumors in Germany--results of 1996 survey].

In the Federal Republic of Germany, no data existed regarding the frequency of open heart surgery for excision of cardiac neoplasms. Therefore, a standard questionnaire concerning heart tumors was sent to all 77 German heart centers performing cardiac surgery. Data from 65 of the 77 heart centers (= 84%) are finally available: 187 patients were operated upon for myxomas, only 44 upon for non-myxomatous cardiac tumors (28 of them with malignant primary or secondary lesions of the heart). In 1996, 0.32% (231/72,763) of all surgical procedures using a heart-lung machine (registered 72,763 of 87,372 total) were aimed at excision of heart tumors. Based on surgical data, the incidence of solely the primary tumors of the heart in Germany is at least 3 per million population per year (253 tumors/81.814 million inhabitants). Even if small tumors are asymptomatic and remain undetected, today, the majority of primary tumors of the heart will be revealed by echocardiography, computer tomography, and magnetic resonance imaging, and these patients are usually referred to operation. Thus, in Germany, about 0.3% of operations using a heart-lung machine were performed for cardiac tumors-among these, myxomas are clearly predominant.

Adolescent↗
PubMed1998

[Pneumatic external counterpulsation--a therapy option in angina pectoris].

Pneumatic external counterpulsation operates by applying ECG-triggered diastolic pressure via cuffs to the vascular bed of the lower limbs. Comparable with intra-aortic balloon pumping, PECP produces a diastolic augmentation combined with increase of mean arterial pressure and coronary perfusion. American, Asian, and our own data demonstrated a reduction of angina pectoris through repeated use of PECP one or two hours daily for four to seven weeks. Exercise testing and thallium scanning confirmed the clinical improvement. PECP is a virtually risk-free treatment option in patients suffering from angina despite medical and interventionell treatment. Opening of collaterals and collateral growth induced by external counterpulsation are discussed as the cause of clinical benefit.

Angina Pectoris↗
PubMed1998

Port-Access coronary artery bypass grafting with the use of cardiopulmonary bypass and cardioplegic arrest.

BACKGROUND: To reduce surgical trauma, we performed minimally invasive Port-Access (Heartport Inc, Redwood City, CA) coronary artery bypass grafting with cardiopulmonary bypass and cardioplegic arrest. METHODS: Thirty-six men and 6 women with a median age of 59 years (range, 31 to 75 years) and isolated lesions of the left anterior descending branch of the coronary artery underwent Port-Access coronary artery bypass grafting. A small (6- to 9-cm) incision was made parasternally on top of the fourth rib. The left internal thoracic (mammary) artery was dissected and taken down through the minithoracotomy either alone or using an additional thoracoscopic approach. Cardiopulmonary bypass was instituted through femoral cannulation, and an additional endoarterial balloon catheter (Heartport Inc) was introduced into the ascending aorta for aortic occlusion, aortic root venting, and the delivery of cold antegrade crystalloid cardioplegia. After cardioplegic arrest, the left internal mammary artery was anastomosed to the left anterior descending artery under direct vision. RESULTS: The median left internal mammary artery takedown time was 49.5 +/- 21.9 minutes, the duration of cardiopulmonary bypass was 59.5 +/- 32.8 minutes, the aortic occlusion time was 28.5 +/- 7.9 minutes, the intensive care unit stay was 1.0 +/- 3.2 days, and the total hospital stay was 5.0 +/- 2.5 days. Intraoperative angiograms were done in the first 10 patients and showed patent left internal mammary artery grafts without anastomotic complications in all cases. Two arterial dissections, including one aortic dissection, were observed in patients with preexisting peripheral vascular disease. The other complications were minor. All but 1 patient recovered well, with no major limitations in their daily activities. CONCLUSIONS: Using this minimally invasive method, sternotomy-related complications can be avoided, the hospital stay can be reduced, and a safe coronary artery bypass grafting procedure can be performed with the advantage of cardiopulmonary bypass and cardioplegic arrest as are used routinely in conventional coronary artery operations.

Adult↗
PubMed1998

[Value of color-coded duplex ultrasound in interstitial laser therapy of hemangiomas and vascular malformations].

BACKGROUND: The diagnosis of hemangiomas and vascular malformations prior to interstitial laser therapy is principally based on clinical and B-mode ultrasonographic examination. Color-coded duplex ultrasonography provides additional information about the vascularization of these tumors. The aim of this study is to evaluate the benefit of this information for the diagnosis and treatment of hemangiomas. PATIENTS AND METHODS: We examined 30 patients suffering from hemangiomas of various sizes and locations. A preliminary treatment plan was developed on the basis of B-mode ultrasonographic examination. This preliminary plan was either verified or changed after obtaining color-coded duplex ultrasonographic studies. RESULTS: In comparison to B-mode ultrasonography, color-coded duplex ultrasonography allows clinically relevant classification of hemangiomas on the basis of their vascularization (no flow, palpation-induced flow, predominantly venous flow, predominantly arterial flow). In 53% of the cases, the preliminary therapeutic plan was modified partially or wholly on the basis of this additional information (new diagnosis, change in the planned surgical approach, and favoring other initial diagnostic and therapeutic options over laser therapy). CONCLUSION: Color-coded duplex ultrasonography provides important additional information compared to B-mode ultrasonography and decisively influences hemangioma therapy. This imaging technique should be recommended for routine preoperative application in hemangiomas.

Adolescent↗
PubMed1998

Enhanced external counterpulsation as a new treatment modality for patients with erectile dysfunction.

Enhanced external counterpulsation (EECP) is a noninvasive treatment modality which can increase arterial blood flow in peripheral and coronary arterial disease. Several studies have demonstrated an increase in the flow of the internal iliacal artery and in carotid and renal perfusion during EECP treatment. We investigated the effect of EECP in patients with erectile dysfunction (ED). Thirteen patients were treated with EECP for 20 days, 1 h per day. Patients reported a significant improvement of penile rigidity after completion of the EECP treatment and a significant improvement of penile peak systolic flow was measured by Doppler sonography. No adverse effects were observed. In conclusion, EECP seems to be an effective treatment modality in patients with ED.

Adult↗
PubMed1997

[Malignant primary tumors of the heart].

Primary tumors of the heart are rare, and a quarter of these tumors prove to be histologically malignant. Benign and malignant primary as well as secondary heart tumors belong to the differential diagnosis when a new heart murmur, heart rhythm disturbances, or cardiac insufficiency appear. In the diagnostics of intracardiac space-occupying lesions, two-dimensional echocardiography represents the method of choice, supplemental examination by computer tomography or nuclear magnetic resonance imaging may be helpful.

Diagnosis, Differential↗