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Biomedical subjects

W Wolf

Publications and source records attributed to W Wolf.

At least 127 records · Page 7Linked to original sources
PubMed1984

Radioiodinated prolactin as a potential mammary tumor localizing agent.

The feasibility of using radioiodinated prolactin for early detection of solid mammary tumors was studied in the rat. Radioiodinated prolactin was first injected into tumored and control rats in order to define the localization of the labeled hormone in their target organs, then it was injected into extracorporeal blood-loop of tumored and healthy rats, in order to study its clearance in those animals. At 15 min post injection, 75-82% of the labeled hormone was recovered, of which 4-5% were counted in the tumor. Deiodination was apparent only 30 min after injection. As much as high deposition of the labeled hormone was not achieved in the hormone-dependent tumor lines investigated, some of the pitfalls that may be encountered are documented. The clearance of the labeled prolactin as determined by the blood-loop technique is 3.3 min in the R3230 tumor, and 6.4 min in the 13762 mammary tumor. The healthy rats had a blood clearance of 4.6 min.

Animals↗
PubMed1984

Early post-natal development of neuronal function in the kitten's visual cortex: a laminar analysis.

The normal post-natal development of visual cortical functions was studied by recording extracellularly from 612 single neurones in the striate and parastriate cortex of anaesthetized and paralysed kittens, ranging in age from 6 to 24 days. Analyses have been made of laminar differences in the developmental trends of receptive field properties such as orientation specificity and spatial organization of 'on' and 'off' zones. At the beginning of the second post-natal week the majority of neurones (76%) only respond to light 'off' (unimodal 'off' neurones). Only later does the frequency of occurrence of unimodal 'on' neurones and of bimodal or multimodal neurones (with spatially segregated 'on' and 'off' zones arranged side by side) increase so that, by the middle of the fourth week, about equal numbers of these three receptive field types are found. The proportion of 'on-off' neurones (with spatially coincident 'on' and 'off' zones) remains low (between 9% and 12%) during the early post-natal period. In layers 4 and 6 of areas 17 and 18 the frequency of occurrence of visual neurones is quite normal even in the youngest kittens, whereas the probability of recording neurones in layers 2/3 and 5 in kittens less than 14 days old is remarkably low and only gradually improves up to the middle of the fourth week. A very rudimentary order in the spatial arrangement of orientation-specific neurones and ocular dominance distribution is observed even in very young kittens. This order improves rapidly and reaches adult levels during the fourth post-natal week. In visually inexperienced kittens, on average 11% of all responsive neurones are selective for the orientation of elongated visual stimuli, and 58% are biased. The proportion of orientation-selective cells begins to increase rapidly about two days after lid opening, and proportions of orientation-selective cells similar to that in the adult are reached by the end of the fourth post-natal week. Orientation-selective neurones in kittens less than 10 days old are only found in layers 4 and 6 and the lower part of layer 3. In layers 2/3 and 5 they are first seen in larger proportions by the beginning of the third post-natal week. Our results show that, during the first post-natal month, the time course of the functional development of visual cortical neurones depends on receptive field type and on intracortical location.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1983

[Demonstration of neo-intima in PTFE-prostheses after venous replacement in dogs].

Because of the danger of thrombosis, venous replacement by prostheses is a yet clinically unsolved problem. We tested the PTFE-prosthesis at the positions of vena cava inferior and iliac veins in dogs. Already eight weeks after operation, the inner surface of the prosthesis was covered by a thin neo-intima, which by light microscopy, scanning and transmission electron microscopy was shown to contain a basal membrane and endothelial cells. This continuous layer may be responsible for the observed low rate of thrombosis. These findings suggest that the PTFE-prosthesis may offer advantages for venous replacement in patients.

Animals↗
PubMed1983

[67Ga]desferrioxamine--HSA: synthesis of chelon protein conjugates using carbodiimide as a coupling agent.

Desferrioxamine-human serum albumin conjugate was prepared at pH 4.7 using a water-soluble carbodiimide and at pH 7.8 using glutaraldehyde. The crude conjugate was purified by dialysis and gel filtration. The efficiency of 67Ga labeling of the purified conjugate was greater than 95%, with good in vitro stability. The specific activity ranged from 5 to 50 microCi/mg. Treatment of the conjugate with urea resulted in a 20--30-fold increase in specific activity, suggesting that a number of chelon groups are unavailable for Ga binding due to non-covalent intramolecular cross-linking.

Carbodiimides↗
PubMed1983

Orientation bias in the response of kitten LGNd neurons to moving light bars.

The orientation sensitivity to moving light bars was determined for 113 neurons in laminae A, A1 and C of the dorsal part of the lateral geniculate nucleus (LGNd) of kittens 7-42 days old. Forty neurons (35.4%) were biased to contrast orientation (OB neurons), i.e. their response to an optimally oriented bar was 2-10 times stronger than their response to a bar oriented orthogonally to the optimal. The remaining 73 neurons were not sensitive to contrast orientation. Evidence is presented that orientation bias in the LGNd develops prior to visual experience. Orientation biased responses in the LGNd strongly depended on stimulus parameters; preferred stimuli were light bars having a length of 5 degrees or more and moving at velocities slower than 5 degrees/s. Our findings suggest that the OB neurons of the LGNd could be effective in generating the early orientation sensitivity in the visual cortex.

Animals↗
PubMed1983

Modulation of natural killer activity by aspirin: I. In vitro effect of aspirin.

It has been previously shown that the Natural Killer (NK) cell activity of peripheral blood mononuclear cells (NMC) from healthy donors can be augmented by in vitro coculture of MNC with melanoma cells. This augmentation was not seen when the blood donors had taken acetylsalicylic acid (ASA) 12 h before venipuncture. To examine the direct action of ASA on the NK cell activity we treated MNC in vitro by ASA and tested the cytotoxic activity on NK-sensitive target cells. Neither the spontaneous NK cell activity nor the in vitro stimulation of NK cell activity by beta-interferon (IFN) was influenced by ASA treatment in vitro.

Aspirin↗
PubMed1983

[Relation between behavior and experience variables in the communication of happy and unhappy couples].

Distressed (n = 7) and nondistressed couples (n = 7) were examined. They had to discuss 4 tasks (2 scenes of the IMC from Olson a. Ryder [1970], one own problem and a proverb ). The Interactions were videotaped and coded with the MICS from Hops et al. (1979). For the operational definition of the experience-variables the Relationship Inventory from Barrett- Lennard (1962) was used. The coherences between observation and questionnaire data are represented and discussed.

Adult↗
PubMed1983

[Some practical aspects of medical examination in sex offenses].

Dispositions are made about some highly important fundamental principles of medical examination and of protection of criminal marks in association with sexual crimes. A model of medical examination is represented. By consideration of these proposals we believe to attain a higher perfection in the evidence of expert opinions.

Female↗
PubMed1982

Effect of pH on tumor cell uptake of radiogallium in vitro and in vivo.

When injected at tracer levels into the blood, radiogallium as 67Ga-citrate binds to, and it transported to the site of the tumor by, transferrin. The process by which transferrin-bound Ga is converted to tumor-bound Ga is not fully understood, but may involve the differential physiology of neoplasms compared with normal tissues. Based on the slight acidity known to be exhibited by the extracellular fluid of many animal and human tumors, we have studied the effect of pH on stability and dissociation of the Ga-transferrin complex and on the uptake of Ga by tumor cells in vitro and animal tumors in vivo. When plasma from rabbits injection 67Ga-citrate was dialyzed at pH 6.5-7.5, dissociation of Ga from transferrin showed an inverse pH-dependence. A similar inverse dependence on pH was observed for the uptake of Ga by L1210 leukemia cells and Ehrlich ascites cells incubated with Ga-transferrin complex. Tumor uptake of Ga in rats bearing Walker-256 carcinosarcoma or Murphystum lymphosarcoma whose tumor pH had been further lowered by administration of glucose showed a statistically significant increase over control rats receiving no glucose. These results demonstrate that the stability of the Ga-transferrin complex is pH-dependent and suggest that dissociation of this complex due to decreased pH at the tumor site may be one factor involved in tumor localization and binding of Ga.

Animals↗
PubMed1982

TSH, T3, rT3 and fT4 in maximal and submaximal physical exercise.

The response of various thyroid hormone parameters to maximal physical exercise (MPE) was investigated in 14 medium and long distance runners and 13 divers. The effects of submaximal long time physical exercise (SMPE) was examined in seven divers. The TSH-level decreases significantly during MPE and slightly rises again after the end of the exercise. In SMPE, however, TSH continuously rises until 15 min after the end of the exercise. The T3 level rises significantly in MPE and falls below the initial value 15 min after the exercise finishes, during SMPE it remains practically unchanged and slightly decreases after the finish. In MPE, the rT3 level does not change and slightly decreases after termination, while the fT4 level continuously decreases from the beginning till 15 min after the exercise period. The latter two parameters do not show any change in SMPE. As possible reasons for the changes of TSH levels a decrease (MPE) or an increase (SMPE) of pituitary secretion might play a role. Furthermore, in MPE the rise in T3 level might be related to hemoconcentration, and the decrease in fT4 level to an elevated cellular utilization.

Adult↗
PubMed1982

Corrective saccades: effect of shifting the saccade goal.

A double step paradigm was used to investigate the saccade control, in particular the role of retinal feedback on correction saccades. The first target step eliciting the primary saccade had an amplitude of 10-15 deg and was followed by a second target step of 3 deg which occurred 0-300 msec after the onset of the primary saccade. The characteristics of the saccadic reactions were analyzed as a function of the time between the end of the primary saccade and the second target step. The data show that correction saccades can be modified when the second target step occurs earlier than 60 msec after the end of the primary saccade. Secondary saccades then are corrective, and their parameters show no differentiation between endogenous and exogenous refixation errors. In further experiments, additional blanking periods were inserted separating the visual system from reafferent information. Under this condition, the system is silent and starts the programming of the correction saccade only when the target is illuminated again. The data demonstrate that retinal feedback is a fundamental part in refixation.

Electronystagmography↗
PubMed1982

Synthesis of indium-labeled antibody-chelate conjugates for radioassays.

A method has been developed to achieve rapid and reproducible complexation of indium to transferrin at pH 7.4. The system consists of nitrilotriacetic acid (NTA) as the intermediate carrier ligand, whose function is to allow the 113m In ion, in a solution in Tris buffer, pH 7.4, to be transferred rapidly to the specific binding sites on transferrin. Just as in the case of iron, this complexation requires the presence of a synergistic ion such as bicarbonate. The present system can be used to allow the binding of 113mIn to transferrin when coupled to an antibody. This method has been tested by studying the conjugation of an antibody, the IgG fraction of goat anti-rabbit-IgG, with either transferrin or desferoxamine, using glutaraldehyde as the coupling agent. Optimization in terms of total protein concentration and glutaraldehyde levels lead to products where the specific metal binding capacity of the transferrin moiety remains unchanged, and where the antibody retains 70% of its antigenic activity. The present system can be considered an extension of the ELISA techniques and can be used to determine, by a terminal 113mIn labeling technique, the level of specific binding of an antibody to its antigen.

Animals↗
PubMed1982

Dosimetry and preliminary human studies of 18F-5-fluorouracil.

The relative distribution, metabolism and kinetics of 18F containing compounds, following administration of 18F-5-fluorouracil, has been proposed as a prognostic aid in predicting response to 5-fluorouracil chemotherapy. Because 18F has a relatively short physical half-life (t1/2 = 110 min), and the distribution and kinetics of the radiolabeled 5-fluorouracil need to be studied over periods of time that range over several half-lives of the radionuclide, significant quantities of the labeled drug must be administered in order to obtain good counting statistics. The distribution of 18F, following injection of 18F-5-fluorouracil to rats and mice, has been well documented in our previous work. It appears that the distribution of 18F in humans, following administration of 18F-5-fluorouracil is similar to that in rats. We calculated the radiation dose according to the MIRD technique for the eleven main target organs for a reference man. The critical organs, according to these calculations, are the bladder wall, the kidney and the liver, receiving a radiation dose of 729, 184 and 114 mrad per mCi injected, respectively.

Animals↗
PubMed1982

Double antibody immunoradiometric assay of hGH employing a terminal labeling technique.

A method is described, and validated for hGH, using a double antibody immunoradiometric assay and a universal antibody coupled to a chelating moiety that can be labeled as the terminal step in the assay procedure. This technique, usable for any antigen, precludes the need for radiolabeled specific antibodies, and because of the short-lived radionuclide used in the terminal labeling step, generates no radioactive waste. The assay itself uses a specific first antibody coupled to a solid support (paper disc) to which the antigen binds. A specific second antibody from a second species is then attached to the solid phase retained antigen. Now a third antibody is attached, which has been generated from a third species against the second antibody acting as an antigen, and which carries transferrin as a chelating moiety. This final complex is labeled with 113mIn and the plot of the percentage of the total activity bound against the hGH concentration provides the derived values for the antigen levels present in the assay solution.

Antibodies↗
PubMed1982

Serum FSH, LH, and testosterone in humans after physical exercise.

The serum levels of FSH, LH, and testosterone were determined by radioimmunoassay in 63 men before, during, and after maximal and submaximal physical short- and long-term exercise (800-n running, climbing, 36-k cross-country skiing). In the 800-meter run, significant elevations of FSH, LH, and testosterone were observed, while in all other field and laboratory test (climbing, 36-km cross-country skiing, maximal stepwise bicycle and treadmill ergometry, 90-min submaximal bicycle ergometry) the hormone levels remained unchanged or were decreased. In contrast to FSH and LH, which did not show any clear modification with duration or intensity of exercise or with the state of training, changes of testosterone in the endurance field test (36-km cross-country skiing) seemed to be training dependent. In highly endurance-trained subjects, there was an increase and in less well-trained subjects a decrease of testosterone for equal distances and intensities of exercise.

Adolescent↗
PubMed1982

Collagenase in the Walker 256 carcinoma. A study of the latent and active enzyme in vivo and in vitro.

A latent form of collagenase had been isolated from crude extracts of the insoluble, fibrous material from Walker tumor homogenates. Purified preparations of this enzyme yielded a major unit of Mr approximately 62000, as determined by gel filtration on AcA 54 Ultrogel. In its activated form collagenase had been purified to apparent homogeneity with an approximate Mr of 42000. The active enzyme cleaved soluble collagen into three-quarter and one-quarter length fragments in the manner of vertebrate collagenases. Latent collagenase from culture media eluted with an apparent Mr of 53000 and was thus slightly larger in size than its activated form that eluted at 42000. Extracted latent collagenase and latent collagenase from culture media could be activated enzymatically by trypsin or chymotrypsin and non-enzymatically by mersalyl, an organic mercurial compound. We suggest that latent collagenase from Walker tumors are complexes of active enzyme with inhibitor(s) of low molecular weight(s) and are not true zymogens.

Animals↗