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Biomedical subjects

F Wolf

Publications and source records attributed to F Wolf.

At least 109 records · Page 6Linked to original sources
PubMed1990

Regional cerebral blood flow during focal seizures of temporal and frontocentral onset.

Ictal single photon emission computed tomography recordings were performed in 9 patients in the course of 11 seizures. Injections of radionuclide were made an average of 72 seconds after the onset of the seizure as indicated by electroencephalography. All patients also underwent interictal recordings. In 6 patients, the localization of the electroencephalographic focus and the morphological lesions corresponded with the ictal hyperperfusion. This could be seen in single photon emission computed tomography. Seizures triggered by hyperventilation, and seizures of patients with anatomical brain lesions (e.g., cysts, surgical defects, and recent injections of technetium-hexamethylene-propylene-amine-oxime) showed an absent or noncorresponding localization of the ictal recording. The ictal and interictal recording seems suitable as a confirmatory noninvasive method for the localization of the epileptogenic focus, particularly in the preoperative evaluation of epilepsy.

Adolescent↗
PubMed1990

Imaging rheumatoid arthritis specifically with technetium 99m CD4-specific (T-helper lymphocytes) antibodies.

CD4 expressing T-lymphocytes are involved in the pathogenesis of rheumatoid arthritis, so the possibility of using radiolabelled CD4-specific antibodies to localise diseased joints was studied. Prospectively six patients with rheumatoid arthritis were investigated. Five of them received 200-300 micrograms of a 555 MBq technetium 99m CD4-specific antibody (MAX.16H5) and were examined with three phase bone scans. Max.16H5 (IgG1) was labelled according to the mercaptoethanol (Schwarz) method. Lymphocytes of one patient were isolated on a Ficoll-Hypaque gradient and labelled with the antibody in vitro. Scans were performed 1.5 h, 4 and 24 h post injection in anterior and posterior views. In all patients, diseased joints could be clearly imaged at as early as 1.5 h. The localisation of the diseased joints correlated (P less than 0.01) with the clinical signs, with the early methylene diphosphonate (MDP) scan (P less than 0.01) and only weakly with the late bone scan (P greater than 0.05). According to these data we conclude that 99mTc-labelled CD4-specific antibodies specifically image actively diseased joints in rheumatoid arthritis.

Antibodies, Monoclonal↗
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

Immunohistochemical identification of CA125 and the F(ab')2 fragments of the murine monoclonal antibody OC125 in ovarian cancer tissue.

Benign and malignant tissue samples of 19 ovarian cancer patients who received an intravenous infusion of radiolabelled F(ab')2 fragments of OC125 were examined for expression of CA125 and the cellular location of the injected antibodies. CA125 could be detected by immunohistochemistry in 47 of 71 biopsies containing cancer cells, but not in 258 biopsies with benign tissue. F(ab')2 fragments were found in 34 of these 47 biopsies. The diffuse intracytoplasmic staining pattern seemed to indicate that the injected antibodies had crossed the membranes of the cancer cells. Since the antibody could not be detected in benign tissues, further applications of OC125 for diagnostic and therapeutic purposes seems to be justified.

Antibodies, Monoclonal↗
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

Resection guided by antibodies (REGAJ): a diagnostic procedure during second-look operation in ovarian cancer patients.

A hand-held probe has been used to localise the 131I-labelled antibody OC125 during second-look operation (SLO) in 22 ovarian cancer patients. In six patients microscopic cancer was detected with the procedure and a further six patients with areas of increased radioactivity during SLO developed recurrent disease within 1-4 months. We suggest examining resection guided by antibodies as a possible means of removing antigen-producing cancerous tissues during surgery.

Antibodies, Monoclonal↗
PubMed1988

Localization and activity of inflammatory bowel disease using 111In leukocyte imaging.

A prospective study was initiated to compare the clinically proven results concerning localization/extent and activity of inflammatory bowel diseases with those of 111In-oxine leukocyte imaging. All patients studied were completely examined with barium enema x-ray, clinical and laboratory investigations, and endoscopy with histopathology. A total of 31 leukocyte scans were performed in 15 patients (12 with Crohn's disease, 3 with ulcerative colitis). The scans were graded by comparing the cell uptake of a lesion (when present) and a bone marrow area providing a count ratio (CR). The inflammatory lesions were correctly localized on 26 leukocyte scans, and in 21 scans the scintigraphically estimated extent of disease was identical to endoscopy. In 5 cases the disease extent was underestimated, 4 scans in patients with relapse of Crohn's disease were falsely negative, and in one patient with remission truly negative. The scintigraphically assessed disease activity was also in a good agreement with clinical disease activity based on histopathology in all cases. We conclude that leukocyte imaging provides valuable information about localization and activity of inflammatory bowel disease.

Adult↗
PubMed1987

Calcium binding by parathyroid cell plasma membranes.

Parathyroid hormone (PTH) secretion from parathyroid glands is controlled mainly by extracellular calcium both in vivo and in vitro. In this study, the Ca2+ binding properties of bovine parathyroid cells have been investigated on a highly purified plasma membrane preparation with flow dialysis techniques. Scatchard plot analysis of the data shows the existence of at least two different binding sites: the high affinity have an apparent Kd1 of 6.6 X 10(-5) M and a capacity (n1) of 20.1 nmol/mg protein. The low affinity sites have an apparent Kd2 of 2.6 X 10(-4) M and a capacity (n2) of 37.7 nmol/mg protein. Furthermore, at higher total Ca2+ concentrations, additional bindings with an apparent Kd3 in the millimolar range and a capacity (n3) of 118 nmol/mg protein are detectable. Neither the apparent Kd's nor n's of these calcium binding sites was affected by isotonic substitution of the medium with NaCl or KCl, while the number of binding sites increased in Choline Cl. On the other hand, the presence of 5-10 mM LiCl in isotonic Na-K medium caused a marked decrease in calcium binding from these sites. LiCl is the only monovalent cation that both in vitro and in vivo is able to enhance PTH release regardless of high or low extracellular Ca2+ concentrations. Therefore the observed displacement of calcium from calcium binding sites seems to be rather specific and could correlate with the observed enhanced PTH secretion in parathyroid cells. It is proposed that the first event in the regulation of PTH secretion by extracellular Ca2+ is the binding of Ca2+ to the low affinity, high capacity sites present on the surface of parathyroid cells and that calcium occupancy of those sites is the necessary event to initiate intracellular signals leading to inhibition of PTH secretion.

Animals↗
PubMed1986

3-Hydroxy-3-Methylglutaryl Coenzyme A Reductase Activity in Ochromonas malhamensis: A System to Study the Relationship between Enzyme Activity and Rate of Steroid Biosynthesis.

3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, the key regulatory enzyme of the isoprenoid pathway, was found to be predominantly microsomal in Ochromonas malhamensis, a chrysophytic alga. Detection of HMG-CoA reductase requires the presence of 1% bovine serum albumin during cell homogenization, and the activity is stimulated by the presence of Triton X-100. The enzyme has a pH optimum of 8.0 and an absolute requirement for NADPH. When grown in 10 micromolar mevinolin, a competitive inhibitor of HMG-CoA reductase, O. malhamensis shows a 10- to 15-fold increase in HMG-CoA reductase activity (after washing) with little or no effect on cell growth rate. Cultures can be maintained in 10 micromolar mevinolin for months. O. malhamensis produces a large amount (1% dry weight) of poriferasterol, a product of the isoprenoid pathway. The addition of 10 micromolar mevinolin initially blocked poriferasterol biosynthesis by >90%; within 2 days the rate of synthesis returned to normal levels. Immediately after mevinolin was washed from the 2-day culture, there was a transient 2.5-fold increase in the rate of poriferasterol biosynthesis. The rate of poriferasterol biosynthesis and the level of HMG-CoA reductase activity both fell to control levels within hours.

Journal Article↗
PubMed1985

The nonspecific clearance function of the reticuloendothelial system in patients with immune complex mediated diseases before and after therapeutic plasmapheresis.

The nonspecific clearance function of the reticuloendothelial system (RES) in six patients with immune complex mediated systemic vasculitis was determined by the evaluation of the disappearance rate of technetium 99m labelled microaggregated human serum albumin colloid (MHAC) injected IV before and after therapeutic plasma exchange. Three patients with systemic lupus erythematosus (SLE) and one patient with immune complex vasculitis (ICV) exhibited a significant clinical improvement after plasmapheresis which was paralleled by an accelerated MHAC elimination rate following plasma exchange therapy. One patient with ICV and unresponsive to plasma exchange showed delayed MHAC elimination. In one patient with myasthenia gravis (MG), the elimination rate was not altered by plasmapheresis. The data obtained indicate that nonspecific clearance of the RES may be one effect of plasma exchange therapy in patients with immune complex mediated diseases.

Adolescent↗