In vivo labeling with1251-CRH of human ACTH-producing pituitary adenomas heterotransplanted to nude mice

Tissue from 23 pituitary adenomas causing Cushing’s disease was implanted subcutaneously into 159 NuNu/NMRi mice, resected after 21 or 35 days, and evaluated histologically and immunohistochemically. After 21 days, 74.3% of the grafts survived, 59% having less than 30% necrotic adenoma cells. After 35 days, 45% of the adenoma fragments survived, 37% having less than 30% necrotic adenoma cells. The preservation of the grafts was essentially dependent on the grade of vascularization accomplished by migration of the host’s capillaries. As assessed by adrenal weight and histologically, biological activity of the transplants could not be detected. Histologically, the grafts maintained the features of their primary tumors, and adrenocorticotropic hormone (ACTH) could be visualized immunohistologically.Seventeen mice with subsequently proved preserved adenoma tissue received an intravenous injection of 12.5 μCi¹²⁵l-corticotropin-releasing hormone (CRH) and light microscopy-autoradiography was performed. Specific labeling, as verified by positive and negative controls, was exhibited by 1 1 of 15 transplants originating from 3 highly differentiated ACTH cell adenomas. Four did not label clearly positive. Two grafts of an undifferentiated mucoid cell pituitary adenoma did not show any labeling.The nude mouse model is a useful tool for the study of ACTH-producing pituitary adenomas in vivo. Highly differentiated ACTH cell adenomas can be labeled with radioactive CRH in vivo.     

Amygdala-prefrontal coupling depends on a genetic variation of the serotonin transporter

Major depression is conditionally linked to a polymorphism of the human serotonin transporter gene (SLC6A4). During the presentation of aversive, but not pleasant, pictures, healthy carriers of the SLC6A4 short (s) allele showed stronger activation of the amygdala on functional magnetic resonance imaging. s carriers also showed greater coupling between the amygdala and the ventromedial prefrontal cortex, which may contribute to the abnormally high activity in the amygdala and medial prefrontal cortex seen in major depression.     

Red cell hemoglobin,hydrogen ion and electrolyte concentrations during exercise in trained and untrained subjects

Summary Red cell concentrations of hemoglobin (MCHC), H⁺, Na⁺, K⁺, Mg⁺⁺, Cl^– were measured in femoral venous blood of six untrained (UT), six endurance trained (TR) and three semitrained (ST) subjects during graded increasing work (4, 8, 12, 18 and 24 mkp/s, 10–15 min on each step) on a bicycle ergometer. Before exercise no significant differences were detected for the measured variables when comparing UT and TR. During exercise MCHC, [Na⁺], [K⁺] and [Mg⁺⁺] remained constant indicating lack of water shift into the erythrocytes in spite of a marked acidosis (lowest pH_Blood value 7.225). This lack resulted from an elevated extracellular osmolality. [H⁺]_Ery and [Cl^–]_Ery maximally increased by 2.0×10^–8 eq/kg H₂O and 10 meq/l, respectively. The change was markedly greater in UT than in TR at equal load. However, if [H⁺]_Ery and [Cl^–]_Ery were related to pH of whole blood, differences between groups almost disappeared and the ions were distributed as predictable from in vitro experiments (Fitzsimmons and Sendroy, 1961). Behaviour of H⁺ and Cl^– may be of importance for oxygen dissociation under in vivo conditions.Supported by Bundesinstitut für Sportwissenschaften, Köln     

Predicting the development of infant emotionality from maternal characteristics

Few studies have examined the associations between environmental conditions and developing infant emotionality or the differential susceptibility to those conditions. The present longitudinal study aims to make a contribution to close that gap. We analyzed whether positive emotionality, negative emotionality/irritability, and withdrawal/fear at the end of the first year of life are predictable from preceding caregiver's depression/anxiety, social support, and sensitivity in the interaction with the infant while controlling for antecedent states of emotionality. Furthermore, the question of whether associations between maternal characteristics and subsequent fear are stronger in the subgroup of infants high in irritability as opposed to those who are low in irritability was investigated. Subjects were 101 healthy firstborn infants and their primary caregivers. Assessments were conducted at infant ages of 4, 8, and 12 months. Depression, anxiety, and the social support of the caregiver were assessed by questionnaire. Sensitivity in the caregiver-infant interaction was assessed by behavior observations within the scope of home visits. Temperament characteristics were observed in standardized laboratory episodes. Whereas negative emotionality and withdrawal/fear were significantly predictable from the maternal characteristics, no predictability could be shown for developing positive emotionality. There were indications of a stronger association between the maternal characteristics and developing withdrawal/fear in irritable infants.     

Characterization of DEAE-dextran by means of light scattering and combined size-exclusion chromatography/low-angle laser light scattering/viscometry

Ten DEAE (2-(diethylamino)ethyl) dextran samples were investigated by means of static and dynamic light scattering, viscometry and size-exclusion chromatography (SEC) in combination with on-line small-angle laser light scattering (LALLS) and viscometry (VISC). In dilute solution the behavior of DEAE-dextran was compared with that of unsubstituted dextran and the molecular weight M dependences of the radius of gyration R_g, hydrodynamic radius R_h, intrinsic viscosity [η], second virial coefficient A₂ and z-average diffusion coefficient D _z were determined. The relationships for DEAE-dextran dissolved in a 0,8 molar sodium nitrate solution were nearly the same as for dextran dissolved in water with 0,05 wt.-% sodium azide and gave the same exponents. The molecular weight dependence of the intrinsic viscosity cannot be described by a Kuhn-Mark-Houwink relationship with a constant exponent. The slope in the plot of log [η] versus log M decreases with increasing molecular weight which indicates the occurrence of branching. By means of SEC/LALLS/VISC measurements the molecular weight distributions were determined. The distributions were calculated (1) directly from the light scattering signal, (2) from a calibration line obtained by light scattering data of a DEAE-dextran sample with a broad distribution and (3) from the intrinsic viscosity distribution obtained by the on-line viscosity/refractive index detector in combination with the [η]-M relationship. In order to get the correct molecular-weight dependence of the intrinsic viscosity it is necessary to determine the molecular weight distribution directly by LALLS (technique 1) and to combine this with the appropriate intrinsic viscosity data from the viscometer. Only the third technique, which is an extension of technique 1, gave satisfactory results over the whole molecular weight region observed.     

Crystalline and disordered state of poly(dihexylsilylene) copolymers

A systematic comparison of random copolymers, derived from poly(dihexylsilylene) (PDHS) by incorporation of monomeric units with shorter unbranched alkyl side chains, has been carried out based on calorimetry, variable temperature UV spectroscopy, and ²⁹Si MAS (magic angle spinning) solid state NMR investigations. Also, hexylmethylsilylene units and branched monomers have been copolymerized. Up to 10% comonomer with shorter linear side chains (i. e., pentyl to propyl) could be incorporated into PDHS without impeding the all-trans order of the crystalline phase. In this case, the UV absorption maximum of the crystalline low-temperature phase was affected only slightly according to the length and fraction of the comonomer side chains. A less ordered crystal structure (λ_max = 345–355 nm) was observed when the content of comonomers with shorter side chains was about 20%. Yet, all these materials form conformationally disordered mesophases. A clear disordering transition and corresponding thermochromism was not observed any more when 50% of propyl side chains were incorporated. The order of the crystalline and the mesophase is also strongly perturbed if only a small fraction (4%) of the side chains are branched at C².     

The relationship between the electromyogram-amplitude and isometric extension torques of neck muscles at different positions of the cervical spine

A group of 12 healthy men volunteered for the experiment. Electromyograms (EMG) were obtained from semispinalis capitis, splenius capitis, levator scapulae, and trapezius muscles. The flexion angle of the cervical spine was precisely adjusted to 0°, 10°, 20°, and 30° relative to the horizontal, with a constant angle of the atlanto-occipital joint. The subjects made eight short (about 2 s) vertical extension forces (6%, 12%,18%, 24%, 30%, 36%, 42%, and 48% of maximal voluntary peak contraction force). For each position, the centre of pressure under the head was determine as the basis for the calculation of the external lever arm. The presence of motor endplate regions was ascertained by multiple surface electrodes. The slopes of individual linear regression lines for the root mean square (rms)-values were dependent on the existence of endplates in the area of the electrodes — endplates caused smaller rms values per Newton metres of external torque. Significant intersubject differences between regression equations could not be eliminated by the normalization of EMG-parameters and/or torques. The elimination of gravity, the continuous monitoring of positions, and the consideration of localization of motor endplate regions were essential prerequisites for the acquisition of reliable relationships between EMG of different neck muscles and external torques. Two important conclusions were derived for the prediction of torques from EMG measurements: firstly, individual regression equations which take into account the position of the head and neck should be used; secondly, normalization procedures do not justify the application of average regressions to a group of subjects.