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Biomedical subjects

W Becker

Publications and source records attributed to W Becker.

At least 73 records · Page 4Linked to original sources
PubMed1990

Bone scan and red blood cell scan in a patient with epidermal naevus syndrome.

A bone scan and red blood cell scan in the rare epidermal naevus syndrome, associated with multiple haemangiomas of the bone and hypophosphataemic osteomalacia in a 20-year-old man are reported. The typical pattern of osteomalacia on the bone scan was associated with lesions of increased bone metabolism in the peripheral bones. The haemangiomas did not pool labelled red blood cells. Thus, the bone scan seems to be suitable for diagnosing the complete extent of haemangiomas in bone, but they could not be specifically proven by red blood cell pooling.

Adult↗
PubMed1990

Lectin binding to cells of Schistosoma mansoni sporocysts and surrounding Biomphalaria glabrata tissue.

The binding of different lectins to the surface of mother and daughter sporocysts of Schistosoma mansoni (Trematoda) and to cells of its intermediate host Biomphalaria glabrata (Gastropoda) was investigated. The test system consisted of several biotin-labeled lectins, an avidin-biotin-peroxidase complex and 3,3'-diaminobenzidine. The fixatives used were Formalin, Bouin's and Zenker's solutions; unfixed material was also studied. Most lectins reacted equally with host tissue and parasite tissue. However, receptors for Ulex europaeus I (most probably fucose) were only demonstrated on daughter sporocysts. Thus, a method was found to specifically mark Schistosoma mansoni daughter sporocysts in the digestive gland tissue of its intermediate host. Mother sporocysts and surrounding host tissue differed in their distribution of galactosyl groups. Both lack fucose and N-acetyl-galactosamine. The differences in lectin binding of galactosyl determinants were also observed during the in vitro development of mother to daughter sporocysts.

Animals↗
PubMed1990

Human oblique saccades: quantitative analysis of the relation between horizontal and vertical components.

Are the horizontal and vertical components of oblique saccades produced by two separate pulse generators or by a single, vectorial pulse generator? To investigate this question, purely horizontal and vertical ("cardinal") saccades as well as oblique saccades with a meridional direction of +/- 45 deg (horizontal and vertical components of equal size) were recorded in 10 human subjects using a magnetic search coil. The components of oblique saccades were slower than cardinal saccades of comparable size, yet the oblique vector velocity was slightly larger than the velocity along cardinal directions. The onset of the two components was always synchronized, but their times to peak velocity and their durations, although approximately equal on average, frequently were different in individual trials; the component velocities were weakly correlated only. Correspondingly, the trajectory of oblique saccades exhibited various types of curvature which often changed from trial to trial. There was no correlation between curvature and aiming accuracy. These results are discussed in terms of various models of saccade generation. It is suggested that each of the two components is generated by its own local feedback pulse generator; the two components would be coordinated by crosscoupling the two local feedback circuits at the level of their error signals. By contrast, the extraretinal feedback that prepares corrective saccades is apparently not evaluated componentwise but may use a vector representation, since the latency of oblique corrective saccades was a function of the vectorial error magnitude.

Data Collection↗
PubMed1990

Class II furcations treated by guided tissue regeneration in humans: case reports.

In the cases reported here, the response of Class II mandibular molar furcation defects to guided tissue regeneration (GTR) versus sham operation was evaluated. Base-line information, including probing pocket depth (PD) and clinical attachment level (CAL) measurements, was recorded after completion of the hygienic phase. Eleven experimental and six control furcations, randomly assigned, are included in this report. The furcations were surgically exposed, using a flap approach and the areas were debrided. On the experimental teeth, Gore-Tex periodontal material was adapted and sutured, using a suspensory suture. The flaps were then sutured tightly, assuring complete coverage to the material. For 1 month all patients were seen weekly and rinsed their mouths with an 0.12% chlorhexidine solution daily. After 4 to 6 weeks the Gore-Tex membranes were removed. Clinical measurements were repeated at 3 and 6 months following surgery. Changes from baseline in PD and CAL were calculated for each case. Results indicated that PD measurements were reduced by both procedures, but the reduction was better for GTR at 3 and 6 months. At six months the test sites showed 2.8 +/- 1.0 mm pocket reduction, while the control sites showed an average of 1.6 +/- 0.9 mm reduction in pocket depth. CAL recordings were improved by both treatments, but were better for GTR at 6 months, with an average gain in CAL of 1.8 mm for the GTR and 0.6 mm for the controls. These cases in which GTR was compared to sham-operated controls indicate that GTR can improve the response to therapy of Class II furcation defects.

Adult↗
PubMed1990

Incidence of hypothyroidism after irradiation of the neck with special reference to lymphoma patients. A retrospective and prospective analysis.

Twenty-eight patients were studied prospectively in order to determine the incidence of hypothyroidism after mantle irradiation for malignant lymphoma. This group was compared with a historical group of 65 patients, among them 36 patients with malignant lymphoma. The mean follow-up was 30 months for the prospective group and 46 months for the retrospective group. The mean thyroid dose for irradiated malignant lymphomas in the prospective and the retrospective group was 45 Gy and 43 Gy respectively. For other tumors with neck irradiation (retrospective group) the mean thyroid dose was 53 Gy. There were no cases of clinical hypothyroidism in our study. As for subclinical hypothyroidism which is characterised by elevated TSH, the incidence was 22% in the prospective group and 3% in the retrospective group, i.e. 8/93 patients showed a hypothyroid dysfunction. Three of the 8 patients with subclinical hypothyroidism had undergone lymphangiography before radiotherapy. Due to the elevated iodine pool a lymphangiogram is considered as a risk factor for hypothyroidism as well as for hyperthyroidism, which we observed twice in the prospective group. Evaluation of the thyroid function before lymphangiography and irradiation as well as regular thyroid function studies during the follow-up are recommended in order to detect hypothyroidism in time.

Adolescent↗
PubMed1990

Dietary linoleate supplementation modulates formyl-peptide receptor expression and functional responses of rat neutrophils.

We studied effects of dietary supplementation with the essential fatty acid (EFA) linoleic acid (LA) to see if neutrophil responses would be modulated. Neutrophils from rats maintained on a diet supplemented with EFA to 10% of the energy content--the high EFA (HEFA) group--showed a significantly higher LA concentration (but similar arachidonic acid content) compared with neutrophils from control rats maintained on a standard diet with 3% of the energy content as EFA. The HEFA group showed a significantly higher neutrophil oxidative metabolism compared with controls in response to N-formyl-methionyl-leucyl-phenylalanine (FMLP), but this response was equal to control values when stimulated by ionophore A23187, sodium fluoride, or phorbol myristate acetate. Similarly, FMLP conferred a more pronounced increase of intracellular Ca2+ in HEFA neutrophils, whereas this response to ionomycin was equal to that in controls. In contrast, HEFA rat neutrophil migration was decreased to 71% of the value in controls in response to FMLP. Similar results were observed for aggregation responses. On A23187 stimulation, HEFA and control neutrophils generated equal amounts of leukotriene B4 and other 5-lipoxygenase products as well as thromboxane B2 and 6-keto-prostaglandin F1 alpha. However, assessment of binding of FMLP labeled with tritium revealed an increase of the low affinity state of the FMLP receptor population. Thus an increased intake of one unsaturated fatty acid, LA, leading to its accumulation in neutrophils, conferred alterations in formyl-peptide-elicited responses, not associated with the formation of the assessed arachidonate-derived mediators, but most likely through the observed modulation of FMLP receptor subpopulations.

6-Ketoprostaglandin F1 alpha↗
PubMed1990

The relationship of retrobulbar hematomas to vision in cynomolgus monkeys.

An experimental model has been developed to measure the effect of retrobulbar hematomas on functional vision in cynomolgus monkeys. In this model, functional vision was quantitated using flashed evoked visual potentials in five monkeys following creation of retrobulbar hematomas. In one monkey used as a control, functional vision remained impaired for 180 minutes following induction of retinal ischemia by increased intraorbital pressure. In two monkeys in which increased intraorbital pressure was relieved by anterior chamber paracentesis following 15 minutes of retinal ischemia, flashed evoked visual potential promptly returned to baseline level. In two additional monkeys in which increased intraorbital pressure was relieved following 30 minutes of retinal ischemia, flashed evoked visual potentials improved but never returned to baseline levels. This study demonstrates the usefulness of flashed evoked visual potentials in measuring functional vision in cynomolgus monkeys. This experimental model should prove useful in evaluating the effects of increased intraorbital pressure on functional vision and the effect of intervention on impaired vision due to retrobulbar hematomas. Further studies with larger numbers of animals are needed to clarify these preliminary studies and document longer-term effects of retinal ischemia secondary to retrobulbar hematomas.

Animals↗
PubMed1990

99mTc-labelled polyclonal human immunoglobulin for localization of inflammatory sites--early in vitro-results.

99mTc-labelled polyclonal human immunoglobulin (HIG) has been shown to be able to localize inflammatory sites. Hypothetically these immunoglobulins bind directly to bacteria, HIG binds directly to Fc-receptors on the surface membrane of leucocytes or HIG simply passes vessels of increased permeability. To collect further information experiments were carried out in vitro with the blood of human volunteers. 0.5 mg 99mTc-HIG, 2 mg 99mTc-human albumin and 0.5 mg 99mTc-labelled murine monoclonal antigranulocyte antibodies were added to in vitro isolated human "mixed" leucocyte pellets and to 30 ml whole blood of 6 healthy volunteers. The whole blood and the directly labelled leucocyte pellet were layered and separated on a discontinuous Percoll/plasma gradient. The activity distribution was measured within the gradient. The 99mTc-HIG labelled gradients showed a significant uptake of the activity within the monocyte band whereas the 99mTc-albumin gradients showed no specific albumin uptake in any cellular band. The 99mTc-antibody labelled gradients showed a significantly increased uptake on granulocytes. It is concluded that in man a specific monocyte-associated uptake and binding mechanism of 99mTc-HIG plays an important role in the localisation of inflamed sites.

Granulocytes↗
PubMed1990

Clinical and microbiologic findings that may contribute to dental implant failure.

Clinical and DNA probe analysis were used to evaluate 36 failing implant sites in 13 patients. Failing implants showed evidence of increased mobility and a high incidence of peri-implant radiolucencies in radiographs. The probing depth was greater than 6 mm in 58% of the sites measured. Moderate levels of Actinobacillus actinomycetemcomitans, Bacteroides intermedius, and Bacteroides gingivalis were detected with DNA probe analysis.

Actinobacillus↗