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Biomedical subjects

H Becker

Publications and source records attributed to H Becker.

At least 91 records · Page 5Linked to original sources
PubMed1989

Aberrant fatty acyl alpha-hydroxylation in human neuroblastoma tumor gangliosides.

Abnormalities of ganglioside structure characterize the neoplastic state, and aberrant glycosylation has been implicated as underlying many new tumor ganglioside structures. However, variations in ceramide structure can also result in novel tumor gangliosides. To address systematically this aspect of ganglioside metabolism, we have initiated a study of the structures of the ceramide species of an oligosaccharide-homogeneous human tumor-derived ganglioside, GM2. The ganglioside was isolated from neuroblastoma tissue and purified by normal-phase high pressure liquid chromatography. Marked ceramide heterogeneity was observed; 18 individual ceramide species of neuroblastoma GM2 were separated by reversed-phase high pressure liquid chromatography and collected. Their structures were determined by a combination of negative- and positive-ion fast atom bombardment mass spectrometry and collisionally activated dissociation tandem mass spectrometry of the underivatized gangliosides. The striking finding was the detection of alpha-hydroxylation of a significant fraction of each of the major fatty acid species (16:0, 18:0, 20:0, 22:0, and 24:1); alpha-hydroxylated species quantitatively represented almost one-fifth of the total tumor GM2 species. Fatty acyl hydroxylation was also detected in the ceramide of several other human tumor gangliosides. In contrast, as previously known, fatty acyl hydroxylation was not detected in the normal human brain gangliosides GM3, GM2, and GM1. We propose that aberrant fatty acid alpha-hydroxylation is a novel and sometimes quantitatively significant characteristic of human tumor ganglioside metabolism.

Ceramides↗
PubMed1989

Immunomodulating therapy of rheumatoid arthritis by high-dose intravenous immunoglobulin.

11 patients with rheumatoid arthritis were treated with intravenous immunoglobulin (IVGG). In 6 patients clinical results were impressive, although lasting responses could be achieved in 3 patients only. This treatment was immunomodulating, since the immunoregulatory T-cell ratio (CD4/CD8) decreased following therapy by reducing CD4-positive cells in-vivo. By use of anti-mu-antibodies as a B-cell specific mitogen, IVGG-treatment was seen to suppress early processes of B cell activation. In parallel to these cellular effects, IVGG led to a reduction in the levels of polyethyleneglycol-precipitated circulating immune complexes as measured by lasernephelometry.

Adult↗
PubMed1989

Potent leukocidal action of Escherichia coli hemolysin mediated by permeabilization of target cell membranes.

The contribution of Escherichia coli hemolysin (ECH) to bacterial virulence has been considered mainly in context with its hemolytic properties. We here report that this prevalent bacterial cytolysin is the most potent leukocidin known to date. Very low concentrations (approximately 1 ng/ml) of ECH evoke membrane permeability defects in PMN (2-10 x 10(6) cells/ml) leading to an efflux of cellular ATP and influx of propidium iodide. The attacked cells do not appear to repair the membrane lesions. Human serum albumin, high density and low density lipoprotein, and IgG together protect erythrocytes and platelets against attack by even high doses (5-25 micrograms/ml) of ECH. In contrast, PMN are still permeabilized by ECH at low doses (50-250 ng/ml) in the presence of these plasma inactivators. Thus, PMN become preferred targets for attack by ECH in human blood and protein-rich body fluids. Kinetic studies demonstrate that membrane permeabilization is a rapid process, ATP-release commencing within seconds after application of toxin to leukocytes. It is estimated that membrane permeabilization ensues upon binding of approximately 300 molecules ECH/PMN. This process is paralleled by granule exocytosis, and by loss of phagocytic killing capacity of the cells. The recognition that ECH directly counteracts a major immune defence mechanism of the human organism through its attack on granulocytes under physiological conditions sheds new light on its possible role and potential importance as a virulence factor of E. coli.

Adenosine Triphosphate↗
PubMed1989

Monoclonal antibody that defines the prostate specific antigen.

A monoclonal antibody to a protein with a single band in the 30-kD region was obtained from fusion of Balb/C mouse spleen cells immunized with epithelial fractions of BPH, with the myeloma cell line P3 x 63 Ag8 6.5.3 by standard procedures. This antigen was characterized in immunobinding studies with various cellular and target antigens and in immunoperoxidase staining.

Animals↗
PubMed1989

Sneddon's syndrome: clinical course and outcome.

Fifteen patients with Sneddon's syndrome presenting since 1979 were re-examined. After a neurological examination, an orienting test of mental ability as well as an electroencephalogram were performed in all patients. In 10 of the 15 patients computed tomography of the brain was performed, too. Preceding reports and the results of the present study have been used to discuss the characteristics and prognosis of Sneddon's syndrome.

Adult↗
PubMed1989

[The effect of preoperative parenteral nutrition on the perioperative course in patients with esophageal cancer].

In 35 consecutive patients who underwent esophagectomy for malignancy the nutritional status was evaluated. 15 patients were estimated to be malnourished and were therefore treated by total parental nutrition (TPN) for 7 days. In the control group (n = 20, no TPN) the nutritional status was normal. TPN corrected abnormal serum parameters with short half-life time. Therefore the nutritional status of both groups was equal at time of operation. The postoperative clinical outcome of both groups was as follows: In TPN-treated patients postoperative hospital stay for 26 days was shorter compared to 32 days in controls, no patients died (vs n = 4), no patient developed sepsis (vs n = 4), no patient developed acute renal failure (vs n = 3). These differences did not reach levels of significance due to the small patient groups. In conclusion our study shows that patients with esophageal cancer and regarded as well nourished seemed to suffer from nutritional deficits. Assessment of the nutritional status by commonly used nutritional parameters does not reveal these deficits.

Adult↗
PubMed1989

Chronic cerebrovascular insufficiency on the xenon CT scan.

Several investigators have described CT-negative low flow areas in TIA and stroke patients in the chronic phase. The emission tomographic SPECT image they employed has, in contrast to the xenon CT method, no direct relation to the x-ray transmission CT scan. The aim of our study was to study the phenomenon of CT-negative low flow areas using the xenon CT method, a method especially well suited for such cases. 57 xenon CT examinations were performed in 40 TIA patients. Flow data from brain tissue which appeared to be anatomically intact in a slice 5 cm above the canthomeatal plane were analyzed. In the TIA group, the flow in the gray matter was found to be significantly lower on the clinically affected side: symptomatic side, 61.8 +/- 14.7 ml/100 g/min; asymptomatic side, 66.4 +/- 15.8 ml/100 g/min (p less than 0.001). In the stroke group, the flow in the white matter was also affected; symptomatic side, 31.2 +/- 9.8 ml/100, g/min; asymptomatic side, 35.3 +/- 11.1 ml/100 g/min (p less than 0.01). Gray matter: symptomatic side, 56.1 +/- 11.4 ml/100 g/min; asymptomatic side, 66.0 +/- 11.0 ml/100 g/min (p less than 0.001). The findings indicate that the appearance of CT-negative low flow areas in TIA and stroke patients during the chronic phase is the rule rather than the exception. Flow adaptation to anatomic changes not discernible by CT can be differentiated from clinically relevant flow impairment only by testing the cerebrovascular reserve.

Aged↗
PubMed1989

Cranial computed tomography and magnetic resonance tomography in cerebrovascular occlusive disease.

CT is the method of choice for acute diagnosis of cerebral infarction. Attention is to be paid to the alterations of the absorption values with time during the infarction course. In particular, the "fogging effect" should be considered in the second and third week when the infarct may not be demonstrable in the simple CT owing to isodensity and lack of signs of space occupation. The xenon CT enables cerebral blood flow to be measured with calculation of regional cerebral blood flow in ml/100 g brain tissue/min. The simple clinical implementation and the good anatomical correlation are advantageous. MR offers a further non-invasive possibility of diagnosing cerebrovascular diseases. MR is especially efficient in detecting small lacunar infarcts in the medullary bed and in the brain stem. The application of gadolinium-DTPA has in particular differential diagnostic significance. In MR angiography, it is to be expected that the large vessels of the neck and brain can be imaged in the future without administration of contrast media.

Arterial Occlusive Diseases↗
PubMed1989

[Nasal high pressure ventilation in obstructive sleep apnea syndrome. Theoretical and practical otorhinolaryngologic aspects].

Nasal CPAP therapy has been found to be the most effective treatment of OSAS apart from tracheotomy. Its long-term application, however, can cause several ENT complications like dryness of the nasal and pharyngeal mucosa, rhinitis and an increased frequency of sinusitis and infections of the lower airways. CPAP therapy is not applicable if nasal resistance is elevated, so that septal correction may become necessary. Unsuccessful UPPP can cause pressure loss through the mouth during CPAP therapy and in this case tracheotomy remains the only alternative. In order to evaluate the clinical significance of flexible nasopharyngoscopy with Mueller's manoeuvre (FNMM), we compared the endoscopic findings of 71 patients with their individual CPAP pressure required to keep their pharynx patent during sleep, 22 patients showed poor pharyngeal wall movement, 23 patients had moderate obstruction (about 50 percent closure) and 26 patients had nearly complete or complete pharyngeal obstruction. We found that patients with poor pharyngeal mobility needed a significantly lower CPAP pressure (mean 9 mbar) than those with nearly complete pharyngeal obstruction during FNMM (mean 11 mbar). Mean CPAP pressure of patients with moderate obstruction was 10 mbar, but this group could not be separated statistically from the other groups, indicating a not exactly defined category. Rhinomanometry showed no differences in nasal resistance between all groups. There was neither a correlation between CPAP pressure and rhinomanometry, nor between CPAP pressure and BROCA Index or distance of palatal arcs.

Airway Obstruction↗
PubMed1989

[Lung perfusion-ventilation scintigraphy in squamous cell carcinoma of the lung].

The effect of tumour size, as determined surgically, and tumour position, as determined by bronchoscopy, on ventilation and perfusion scintigraphy was examined in 53 patients with squamous cell carcinomas of the lung. The findings were compared with reduction in one-second-capacity. Central tumours were frequently associated with marked reduction in perfusion. In these patients there was a linear positive correlation between ventilation and one-second-capacity. The reduction in perfusion, and the need to measure this, became with more peripheral tumours. There was a correlation between ventilation and tumour size in patients with V/Q quotient of greater than 1.2. The results show that tumour size and position do not necessarily indicate operability. For planning surgery of central tumours, perfusion scintigraphy therefore occupies an important position.

Aged↗
PubMed1989

Prostaglandin E1 and nitroglycerin reduce pulmonary capillary pressure but worsen ventilation-perfusion distributions in patients with adult respiratory distress syndrome.

Pulmonary artery hypertension associated with adult respiratory distress syndrome (ARDS) may increase microvascular filtration pressure by increasing pulmonary capillary pressure (PCP). To evaluate the potential to reverse this consequence of pulmonary artery hypertension, the effects of short-term vasodilator treatment were compared with prostaglandin E1 (PGE1) or nitroglycerin (NTG) on pulmonary hemodynamics and gas exchange. The two vasodilators were infused in ten patients with mild or moderate ARDS at a dosage rate achieving a 20% reduction of the mean arterial pressure. PCP was estimated by graphic analysis of the pulmonary artery occlusion curve, and continuous ventilation-perfusion (VA/Q) distributions were assessed using the multiple inert gas technique. At the given dosages both drugs induced equivalent reductions of the mean pulmonary artery pressure (PAP) from 28.2 +/- 3.6 to 23.7 +/- 3.2 with PGE1 and to 23.4 +/- 3.2 mmHg with NTG. The right atrial and pulmonary artery wedge pressure (PAWP) were also decreased to the same extent associated with the expected decrease in PCP from 17.4 +/- 2.6 to 15.1 +/- 3.3 with PGE1 and to 15.6 +/- 2.7 mmHg with NTG. The estimated PCP values were closely correlated with the values calculated according to Gaar's equation (r = 0.822. n = 23, P less than 0.001) with a regression close to the identity line. The contribution of pulmonary venous resistances to the resistance of the whole pulmonary vascular bed computed as the ratio (PCP- PAWP)/(PAP-PAWP) was 0.28 and remained unchanged during vasodilator infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

[Diagnosis of the function of respiratory control in patients with obstructive sleep apnea syndrome].

UNLABELLED: Twenty-five patients with OSAS were investigated and compared with an age-matched control group of 20 healthy volunteers. The ventilatory responses to pure oxygen administration, active hyperventilation, progressive hyperoxic hypercapnia and progressive isocapnic hypoxia were studied in all subjects. RESULTS: Hypoxic ventilatory response in OSAS patients was significantly diminished as compared with the control group. Hypercapnic ventilatory response, decrease in ventilation due to chemoreceptor inactivation during oxygen respiration and after hyperventilation did not differ in the two groups. The diminished response to hypoxia in OSAS patients was correlated with the increased respiration-synchronous changes in nasal resistance. Our data seem to suggest that in OSAS patients the diminished responsiveness to hypoxia may increase the likelihood of nocturnal apnea. A decrease in hypoxic inspiratory drive appears to be one mechanism initiating upper airway occlusion.

Carbon Dioxide↗
PubMed1989

[Long-term acceptance of nasal continuous positive airway pressure therapy in 70 patients with sleep apnea over a 6-month treatment period].

NCPAP therapy is considered to be an effective method of treatment in cases of obstructive and mixed sleep apnea (SA). We investigated its effectiveness during initiation of therapy, and the acceptance of the ambulatory long-term treatment. Here we present the first 70 patients (68 m, 2f) treated with nCPAP for at least six to a maximum of 20 months (on average: eleven months). Sixty-seven of the 70 patients were effectively treated with a nCPAP pressure of 5-15 mbar. The apnea index was reduced from 49 apnea episodes per hour (range 12-125) to 2 episodes per hour (range 0-8) on average. Therapy failed in one case (anatomical defect of the nasopharynx) and had to be abandoned in two cases (claustrophobia, acute rhinitis). Sixty-three patients, decided in favour of ambulatory long-term therapy. These patients were asked to complete a questionnaire about their experience with nCPAP. Four patients abandoned therapy (all within the first four weeks because of intolerance towards the apparatus), and one patient died 10 days after terminating treatment of an infection of the upper airway. Fifty-eight patients (82% of all) are still undergoing treatment. Eighty-eight per cent of these are using nCPAP for 5-7 nights a week throughout the entire sleep period, or at least for five hours. All patients report a marked reduction in or elimination of subjective symptoms. Mild local side effects occur quite frequently, but can be greatly reduced or eliminated in most cases. In individual cases they lead to a shortening of the nocturnal duration of application.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Does determination of atrial natriuretic factor have significance in the assessment of cardiac stress in apnea in sleep apnea patients?].

It has long been known that the heart is involved volume regulation. This fact took on new importance when, in 1981, de Bold discovered the existence of ANF. Apnea-associated cardiovascular changes make the treatment of apnea necessary to prevent the occurrence of cardiovascular sequelae. What is needed, however, is a parameter which, non-invasively, reflects both the cardiac loading during apnea and effects of treatment. Krieger succeeded in demonstrating that the commonly observed nycturia regresses under nasal cPAP therapy. This prompted us to consider whether the ANF factor might not be involved. In an attempt to find an answer, we have, up to now, investigated six patients prior to and during nCPAP therapy. On the basis of the results we obtained, the following conclusions may be drawn: 1. During apnea, the patients show sometimes dramatic increases in ANF plasma levels. 2. Under nasal CPAP treatment, these elevated levels decrease again, in some cases by as much as 50%. 3. The ANF plasma level correlates with pulmonary arterial pressure. This suggests to us that ANF determination is of importance for the assessment of cardiac loading during apnea, and represents a parameter that reflects the effects of therapy.

Atrial Natriuretic Factor↗