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Biomedical subjects

R Weber

Publications and source records attributed to R Weber.

At least 235 records · Page 13Linked to original sources
PubMed1995

Acute coronary occlusion secondary to radiofrequency catheter ablation of a left lateral accessory pathway.

A case of asymptomatic acute coronary occlusion secondary to radiofrequency catheter ablation of a left lateral accessory pathway is reported. Due to post-procedural ST modifications of the surface ECG, a coronary angiography was performed which disclosed total occlusion of the first marginal branch of the left circumflex coronary artery. Acute myocardial infarction was confirmed by moderate cardiac enzyme release, abnormal myocardial perfusion scan and mild lateral hypokinesia at echocardiography. This rare but potentially harmful complication of interventional electrophysiology should be kept in mind and coronary angiography performed immediately when coronary occlusion related to radiofrequency application is suspected.

Catheter Ablation↗
PubMed1995

Evidence for a lymphotropic nature of circulating plasmacytoid monocytes: findings from a case of CD56+ chronic myelomonocytic leukemia.

Because the cells previously designated plasmacytoid T cells share major immunophenotypic features with cells of the mononuclear-phagocyte system, they have been re-named and are now known as plasmacytoid monocytes (PM). We describe a unique case of chronic myelomonocytic leukemia with circulating PM. The patient, a 48-year-old man, presented initially with refractory anemia. Four years later his general condition deteriorated, accompanied by an increase in leukocytes to 200,000/microliters blood. The bone marrow histology was interpreted as compatible with a diagnosis of chronic myelomonocytic leukemia. Two months before he died, the patient developed generalized lymphadenopathy clinically simulating malignant lymphoma. Histologic examination of an axillary lymph node revealed diffuse infiltration by PM. The PM in the lymph node and some circulating cells closely resembling PM expressed L-selectin, a finding that could be interpreted as a morphologic correlate of their marked lymphotropism. The detection of large numbers of CD56/CD33 double-positive circulating blast cells by FACS analysis strongly supported the diagnosis of a leukemia of myelogenous origin. The patient died of tumor cachexia. Autopsy revealed widespread leukemic infiltrates (always containing clusters of PM) in bone marrow, spleen, liver, lymph nodes, and mucosa-associated lymphoid tissue of the oropharynx. The final diagnosis was one of chronic myelomonocytic leukemia with marked lymphotropism and partial differentiation towards PM. We consider that the rare instances of a hematologic tumor with differentiation towards PM should be classified amongst the myelogenous leukemias.

Antigens, CD↗
PubMed1995

Prevention of vascular remodelling in cardiovascular disease.

The early detection of arterial wall transformations that may further evolve into atherosclerosis may help to identify high-risk patients among the hypertensive population and to select the most appropriate treatment. Intima-media layer thickening that affects a number of hypertensive subjects may potentially represent an indicator of accelerated atherosclerotic transformation of the vessel wall. Diagnosis and quantification of these early changes preceding plaque development should make it possible to determine whether antihypertensive treatment can restore normal wall structures in addition to normalizing the blood pressure. This article reviews some of the new approaches developed in our laboratory to assess both structure and function of conduit vessels. Preliminary data suggest that it is feasible to identify minute geometrical changes in hypertensive subjects long before major vascular lesions occur. This opens a whole new field of investigation into early arterial remodelling, a potential precursor of atherosclerosis.

Adaptation, Physiological↗
PubMed1995

Flow-diameter phase shift. A potential indicator of conduit artery function.

This study assesses (1) the relation of the very-low-frequency vasomotion (< 0.02 Hz) of the radial artery of young healthy volunteers to regional blood flow and (2) its distribution in the upper extremities. Radial artery diameters from comparable sites were measured on contralateral extremities in 18 young healthy volunteers by an echo tracking system simultaneously with blood flow velocity determined by continuous wave Doppler and blood pressure acquired by photoplethysmography in the middle finger. A synchronous global pattern of vasomotion was detected on contralateral radial arteries, suggesting the presence of either a centrally located pacemaker or a humoral system. Modulation of sympathovagal balance in 8 subjects did not significantly alter either the frequency or amplitude of the very-low-frequency vasomotor waves. Matching patterns of diameter and flow oscillations of the very-low-frequency type recorded at the same site were obtained in 10 strictly nonsmoking volunteers for given periods of time. A consistent phase lag was observed between flow and diameter signals. Flow always preceded the diameter fluctuations by a mean (+/- SEM) course of 20.8 +/- 1.56 seconds. Although the physiological basis for oscillatory behavior remains for the moment highly speculative, these results suggest that the very-low-frequency vasomotion pattern in this conduit vessel might be a flow- or shear stress-dependent phenomenon. Shear stress changes at the endothelium modulate vascular tone through the release of vasodilators. The noninvasive assessment of the diameter-flow relation may thus offer a new way of addressing vascular wall function in medium-sized and large arteries in subjects with cardiovascular risk factors.

Adult↗
PubMed1995

Postischemic blood flow response in hypercholesterolemic patients.

We undertook this cross-sectional study to compare the mechanical behavior and postischemic response of the radial artery of 15 newly diagnosed hypercholesterolemic patients with those of 15 age- and sex-matched normocholesterolemic control subjects and 21 hypercholesterolemic patients treated for 2 years with an 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (simvastatin, 10 to 20 mg/d). At the time of the study total cholesterol levels were at 7.9 +/- 0.2, 4.9 +/- 0.2, and 6.0 +/- 0.3 mmol/L in the three groups, respectively (mean +/- SEM, P < .001). High-resolution, noninvasive echotracking for assessment of internal arterial diameter was combined with measurements of blood flow velocity by Doppler and blood pressure by photoplethysmography. Radial cross-sectional compliance and distensibility were similar in all groups. Forearm blood flow and flow-mediated dilation were measured after a 5-minute upper arm occlusion. Flow was calculated from the vessel diameter and blood flow velocity recorded simultaneously at the same site. Flow-mediated dilation after ischemia was not significantly different among the three groups. However, forearm blood flow increase was markedly blunted (P < .01) in untreated hypercholesterolemic patients (211%) compared with the normocholesterolemic control subjects (411%) and treated patients (365%). These findings suggest that the distensibility of the radial artery, a muscular conduit vessel usually devoid of atherosclerotic lesions, and its flow-mediated dilation are preserved in hypercholesterolemic patients. In contrast, forearm resistance vessels exhibit a markedly reduced postischemic blood flow response that may be restored by prolonged lipid-lowering intervention.

Adult↗
PubMed1995

Effects of oxygenation and the stress hormones adrenaline and cortisol on the viscosity of blood from the trout Oncorhynchus mykiss

Although the concentrations of the stress hormones adrenaline and cortisol in rainbow trout (Oncorhynchus mykiss) blood increase upon hypoxic exposure, the combined effects of these hormones and O2 lack upon fish blood rheology have not been investigated. Deoxygenated blood taken by caudal puncture exhibited lower viscosities than oxygenated samples at low shear rates, whereas the opposite was true at high shear rates. However, blood from cannulated trout had similar viscosities in its deoxygenated and oxygenated states. In the deoxygenated state, addition of adrenaline lowered viscosity at low shear rates and increased it at high shear rates, resembling the effects of deoxygenation observed in blood taken by venepuncture. In oxygenated blood on the contrary, no marked adrenaline effects were observed. In deoxygenated blood, addition of cortisol lowered viscosity at all measured shear rates compared with blood without cortisol. In oxygenated blood, however, no cortisol effects were observed. The viscosity effects observed in the presence of cortisol could not be attributed to concomitant changes in haematological variables, However, the effects in the presence of adrenaline manifested in deoxygenated 'cannula' blood and in uncannulated blood without added hormones appear to result from parallel increases in haematocrit and cell volume.

Journal Article↗
PubMed1995

[Association of gastroesophageal reflux and chronic laryngitis].

There is some evidence from anglo-american clinical and experimental studies that gastro-esophageal reflux is more common in patients with laryngitis. Within the framework of an open study, 32 patients with reflux esophagitis and laryngitis were treated with 20 mg omeprazole daily. After 4 weeks at the latest, in all cases inflammation of the esophagus and larynx had healed completely and the patients were without complaints. Suggesting that reflux is the underlying etiology patients with laryngitis seem to benefit from omeprazole.

Adult↗
PubMed1995

[Current aspects of frontal sinus surgery. IV: On therapy of frontal sinus osteoma].

Osteomas are the most common benign tumors of frontal sinus. We evaluated 15 patients with osteomas of the frontal sinus who were managed between 1979 and 1992. The average duration of follow-up was 33 months. In 4 cases osteomas were removed completely via the endonasal route using a microscope and endoscope. We recommend performing a frontal sinus drainage-type 3 primarily. Indications are osteomas of the posterior wall of the frontal sinus located close to the infundibulum. For osteomas of the anterior wall and those located laterally or for very large osteomas we prefer the osteoplastic approach. Apart from the excellent exposure this latter procedure also provides good aesthetic results after carefully placed incisions and precise replacement of the bone flap. We recommend the bicoronal incision in patients with large frontal sinuses, women, or in the presence of good hair growth. Incisions are best placed in a frontal crease in patients with hair loss or a, small frontal sinus.

Adult↗
PubMed1995

[Current aspects of frontal sinus surgery. I: Endonasal frontal sinus drainage in inflammatory diseases of the paranasal sinuses].

Most conditions of the frontal sinus requiring surgery can now be managed successfully by endonasal procedures. According to Draf, 3 types of frontal sinus drainage occur. Surgical techniques and indications are described. In a retrospective study we evaluated 132/648 patients who were on average 5 years postoperative. Forty-two patients had type 1, 43 patients had type 2 and 47 patients had type 3 drainage. Endoscopy revealed a normal mucosa in 56-67%, whole polyps were found in 9-15%. There was no recurrence of an orbital or endocranial complication. According to our definition of surgical success, there was a success rate of 83.4% with type 1 drainage, 83.7% with type 2 drainage and 89.4% with type 3 drainage. If there was only little chance for successful endonasal surgery with type 3 drainage, an external osteoplastic frontal sinus operation was performed for definitive therapy.

Drainage↗
PubMed1995

[Current aspects of frontal sinus surgery. II: External frontal sinus operation--osteoplastic approach].

Most inflammatory diseases of the frontal sinus requiring surgery can now be managed successfully by endonasal procedures. There remain, however, a number of problematic cases in which optimal exposure of the entire frontal sinus is required with possible complete removal of the mucous membrane and sinus obliteration. These remain indications for osteoplastic frontal sinus surgery. Depending on the individual situation, incisions can be chosen that are bicoronal, placed in a frontal crease or positioned below the eye-brow. Surgical techniques are described in detail. Osteoplastic surgery of the frontal sinus with fat obliteration is a reliable and safe method, particularly for management of so-called "difficult" frontal sinuses.

Adipose Tissue↗
PubMed1995

[Physiopathology of left ventricular hypertrophy].

Left ventricular hypertrophy (LVH) is an early complication of hypertension. To a certain degree, this process counteracts the parietal stress induced by high blood pressure. Genetic factors, obesity, high salt diet and different growth factors, notably angiotensin II and noradrenaline, can also predispose to hypertrophic cardiomyopathy. Left ventricular mass is increased on echocardiography in about 20% of hypertensive subjects. LVH is initially associated with a change in myocardial diastolic function and later with abnormal systolic function. It is a major risk factor, a cause of cardiac failure, reduction in coronary reserve and of ventricular arrhythmias. Treatment of hypertension is associated with regression of LVH and preservation or improvement in myocardial diastolic and systolic functions. The decrease in left ventricular mass could reduce the incidence of cardiovascular complications in hypertension.

Electrocardiography↗
PubMed1995

[Aspects of frontal sinus surgery. III: Indications and results of osteoplastic frontal sinus operation].

The osteoplastic approach is indicated for frontal sinus surgery if optimal exposure of the entire frontal sinus is required for possibly complete removal of the mucous membrane and sinus obliteration. In a retrospective study we evaluated 75 patients whose osteoplastic frontal sinus operations were performed in Fulda between 1979 and 1992 and examined indications for surgery, complications and outcome. All patients were examined clinically and subjective complaints were recorded. Indications for surgery were trauma (43), acute and chronic infections (19), tumors (11) and sinus pneumatoceles (2). The overall aesthetic and functional outcome was excellent. Revision was necessary in one only patient, who had forced air into his frontal sinus by nose-blowing too early to create a threat of infection. No serious complications occurred, such as surgery-related meningeal injury or impaired or double vision. One patient needed a blood transfusion because of hemorrhage due to operation (1.3%). The main advantage of the coronal incision used was preservation of the supraorbital nerve bundle without subsequent nerve dysfunctions. Besides optimal exposure of the whole frontal sinus, precise replacement of the osteoplastic flap and choice of incision also lead to a good aesthetic result.

Abscess↗
PubMed1995

[Multi-media technique applied to surgical education].

Multimedia technique applied for surgical training: the microscopic-endoscopic sinus surgery. Multimedia technology is characterised by the integration of several communication media and by an interactive access. New or difficult surgical techniques are made easier and safer thanks to a new program developed for training microscopic-endoscopic sinus surgery.

Computer-Assisted Instruction↗
PubMed1995

The presence of Enterocytozoon bieneusi spores in the lamina propria of small bowel biopsies with no evidence of disseminated microsporidiosis. Enteric Opportunistic Infections Working Group.

Enterocytozoon bieneusi is the most frequently reported microsporidial infection of humans. In patients with the acquired immunodeficiency syndrome, Enterocytozoon infects the lining epithelial cells of the small intestine, hepatobiliary tract, and gallbladder. Because Enterocytozoon has been thought to be limited to infecting lining epithelial cells, the mechanism of spread of E bieneusi within the intestine, to the biliary tract, and, in two case reports, to distant organs remains unknown. This report describes a patient with acquired immunodeficiency syndrome and intestinal microsporidiosis due to E bieneusi. Histopathologic examination of well-oriented biopsies from the duodenum and jejunum revealed both intra- and extracellular spores of Enterocytozoon extending deeply into the lamina propria, where they were located adjacent to capillaries. The patient has not developed disseminated disease 20 months after the initial diagnosis. In this patient, the demonstration of E bieneusi spores in extraepithelial tissues does not appear to be associated with development of subsequent systemic infection.

Acquired Immunodeficiency Syndrome↗
PubMed1995

[Patient-controlled analgesia (PCA) after urologic interventions].

Patient-controlled analgesia (PCA) is a well-accepted technique in postoperative pain management. We used PCA in three different protocols to find the optimum application form. Our study compared 100 patients with radical prostatectomy or transperitoneal tumor nephrectomy in three groups using piritramide. Group 1 (n = 16) received 1.2 mg/h continuously and a 3 mg bolus with a lock-out time of 90 min. Group 2 (n = 30) received 0.8 mg/h continuously and a 3 mg bolus with a lock-out time of 60 min. Group 3 (n = 54) received the same continuous infusion, but the lock-out time was only 30 min. After 24 hours we evaluated the quality of analgesia using VAS scale. The quantity of piritramide was equal in all groups (35.1 mg). An average of seven bolus applications were made during the observation period. In 27.6% of the patients (group 1: 30.4%; group 2: 35.0%; group 3: 23.1%) the bolus demand was refused by programme. The analgesia level was satisfactory in each group, with a VAS value of 27. There was no respiratory depression observed. In conclusion, on-demand analgesia proved to be a good and practicable method in postoperative pain management. Although the dosage of piritramide was not different in the three groups, we recommend the protocol of group 3 because of the lower refusal of bolus application. Therefore, this seems to be the best patient-adapted application form. Even though respiratory complications in the group 3 scheme are not expected, monitoring of respiration and vigilance are recommended.

Adult↗
PubMed1995

Effects of chemotherapy in patients with dental implants.

Endosseous implant placement is generally considered to be contra-indicated in patients undergoing chemotherapy for the treatment of cancer. A case is presented where a patient was diagnosed with cancer and began chemotherapy four weeks after endosseous implants were placed. The impact of chemotherapeutic agents on endosseous implant acceptance as well as upon oral tissue is examined.

Abdominal Neoplasms↗
PubMed1994

[Sputum examination in the diagnosis of Pneumocystis carinii pneumonia in HIV-infected patients].

To assess the sensitivity and negative predictive value of sputum examination for Pneumocystis carinii in HIV-positive patients, follow-ups were performed in HIV-infected patients who had been investigated for the presence of Pneumocystis carinii (376 examinations of sputum and 71 bronchoalveolar lavages). Pneumocystis carinii pneumonia was diagnosed 65 times in 64 patients (57 male and 7 female, median age 35 [23-67]years). In 52% of the cases (n = 34) the pathogen was identified in the sputum, in 48% (n = 31) by means of the bronchoalveolar lavage. Of 342 negative findings in sputum examination, five were definitely false negative since the subsequent lavage yielded pneumocysts. In nine further cases Pneumocystis carinii pneumonia could not be excluded because of the course of the disease. In patients from whom sputum samples were available the sensitivity of pathogen identification was at least 70.8% and the negative predictive value at least 95.9%. Since preceding prophylaxis did not render identification in the sputum more difficult, examination of spontaneous or provoked sputum is indicated as a first hand measure in all patients infected with HIV in whom Pneumocystis carinii pneumonia is suspected.

AIDS-Related Opportunistic Infections↗