Gonadoblastoma: clinicopathologic correlation in six patients

Six patients with a total of nine gonadoblastomas are presented; three--and possibly a fourth--had dysgerminomatous overgrowth which was massive in two patients. Calcification detected by abdominal films was present in three sufficient for preoperative diagnosis. All patients were found to have a Y stem line on peripheral leukocyte chromosome cultures except one patient, who had a 46 XX/45 XO karyotype. She was found to have Y chromatin bodies in the germ cells of her tumor which was in a normal ovary found at exploration for an ectopic pregnancy. Three were found in virilized phenotypic females investigated for amenorrhea, and two for therapy of pelvic masses due to dysgerminomatous overgrowth. Y chromatin studies are reported on gonadal tissue.     

Histology of the endometrium in long-term use of a sequential oral contraceptive

Non-atypical adenomatous hyperplasia was found in 13.5% of 111 biopsies obtained from long-term, predominantly black, users of Oracon. An association between length of time of use (95 cycles for those with adenomatous hyperplasia versus 73 for those without) and the development of adenomatous hyperplasia was noted, but there was no association with hypertension or obesity. Cystic glandular dilatation was seen in 63% but was not thought to represent hyperplasia. No more advanced lesions were seen.     

Experimental investigation of the morphology and stability of diffusion and edge flames in an opposed jet burner

The stability of methane/air and hydrogen/air flames in an axisymmetric counterflow burner was investigated experimentally for different burner geometries, degrees of fuel dilution, and combinations of flow velocities. Both planar diffusion flames and edge flames were observed, and the transitions between these flame types were studied. The experimental results confirmed previously published numerical predictions on diluted hydrogen/air flames: the existence of two distinct stable flame types; the possibility of switching between the two flame types by perturbing the flames, e.g., by suitably changing a flow velocity; and the strong hysteresis for the transition from one flame type to the other. Flame stability diagrams were compiled which delineate the range of fuel and air flow velocities for which the planar diffusion flame and the toroidal edge flame are stable. The lower boundary curve for the edge flame stability exhibits a characteristic minimum at a well-defined value of the fuel velocity. For fuel velocities lower than this value, the transition between the edge and the diffusion structure is reversible, and the flames exhibit bistable behavior. For higher fuel velocities, the decrease of air velocity leads to the extinction of the edge flame. An investigation of both the cold and the reactive flow field identified bistable behavior for the flow field as well. Except for very low flow rates, the stagnation plane stabilizes in two positions, close to either of the two nozzles. Detailed numerical simulations of hydrogen flames capture the essentials of this behavior. The observed flame extinction results from the interaction of the flame dynamics with the dynamics of the flow field.     

Discovery and preliminary pharmacology of Sch 37370, a dual antagonist of PAF and histamine

From a series of amide analogs of the histamine H₁ antagonist, azatadine, a potent, orally active, dual platelet-activating factor (PAF) and histamine antagonist, Sch 37370, namely 1-acetyl-4-(8-chloro-5,6-dihydro-11H-benzo-[5,6]cyclohepta[1,2-b]pyridin-11-ylidine)piperidine, was discovered. Sch 37370 selectively inhibits PAF-induced aggregation of human plateletsin vitro (IC₅₀=0.6 μM), andin vivo inhibits PAF- and histamine-induced bronchospasm in guinea pigs with ED₅₀ values of 6.0 and 2.4 mg/kg p.o., respectively. Sch 37370 is expected to be more efficacious than single mediator antagonists in allergic diseases, such as asthma. Based on papers presented at the Third International Conference on Platelet-Activating Factor and Structurally Related Alkyl Ether Lipids, Tokyo, Japan, May 1989.     

Analysis of inter-fragmentary movement as a function of musculoskeletal loading conditions in sheep

It is well accepted that inter-fragmentary movement influences the fracture healing process. Small axial movement can stimulate callus formation whereas larger shear movement delays the healing process. It is, therefore, essential for optimal fracture healing to minimize shear and to control axial movement. Unfortunately, the complex gap movements are mostly unknown under the large variety of clinical as well as experimental conditions of fracture fixation. To further understand the complex interactions of musculoskeletal loading and inter-fragmentary movements in bones and to reduce the need for animal experiments, a three-dimensional (3D) musculoskeletal model of the left hind limb of a sheep was developed. From 3D ground reaction forces and inverse dynamics, resultant joint loading was determined over a gait cycle. Muscle and joint contact forces were derived from an optimization routine and internal loads in the tibia and metatarsus from beam theory. Finally, inter-fragmentary movements were calculated from the bony loading condition and experimentally determined stiffness matrices of monolateral AISF external fixator constructs. Both the joint contact forces at the hip and gap movement of a mid-shaft tibial fracture agree with in vivo data reported in the literature. The bones proved to be mainly axially loaded with slightly increasing shear forces toward their ends. The results suggest that inter-fragmentary movement of metatarsal fractures is fairly independent of the fracture location whereas the movement increases in proximal tibial fractures compared to those in the distal and diaphyseal tibia. Considerable shear movement was found for all locations and external fixator mountings. However, shear movement could be minimized with a cranio-lateral rather than a cranio-medial shift from the cranial fixator plane.     

In vitro glucocorticoid receptor binding and transcriptional activation by topically active glucocorticoids

BACKGROUND: To study body composition at the whole-body level in patients with Crohn's disease and a history of intestinal resection compared with healthy controls, we performed a cross-sectional study using dual-energy X-ray absorptiometry (DXA). METHODS: Thirty-one patients, 13 men and 18 women, were included. They had a history of Crohn's disease for a mean period of 20 years (range, 4-45 years). All patients had undergone intestinal resections. The colon had been resected in 24 patients, and the mean length of the resected small intestine was 97 cm (range, 0-305 cm). At the time of investigation the Crohn's disease had been in remission for at least 24 months. Patients presented with significantly increased faecal volume and faecal fat excretion. A group of 69 women and 19 men were investigated with DXA and used as reference group. The fat-free mass (FFM), fat mass (FM), percentage fat mass (FM%), and total body mineral content (TBMC) were measured by DXA, and the results were expressed as a z-score. RESULTS: The mean z-score of the body mass index (BMI) was significantly reduced to -0.35 (P=0.036). The FFM was significantly reduced with a mean z-score of -1.74 (P=0.0001). The FM was unchanged (z-score, 0.12; P=0.42). However, FM expressed as percentage of body weight was significantly increased, with a z-score of 0.88 (P=0.001). The TBMC was significantly decreased, with a mean z-score of -1.42 (P=0.0001). There was positive direct correlation between the BMI and TBMC z-scores. There was no correlation between malabsorption and body composition variables. CONCLUSION: Patients with clinically quiescent Crohn's disease showed significant changes in body composition, with low BMI, significant loss of FFM, and unchanged FM. However, when expressed as percentage of body weight, FM was significantly increased. The TBMC was significantly reduced.     

An experimental and numerical study of the structure and stability of laminar opposed-jet flows

Experiments, simulations, and numerical bifurcation analysis are used to study the incompressible flow between two opposed tubes with disks mounted at their exits. The experiments in this axisymmetric geometry show that for low and equal Reynolds numbers, Re, at both nozzles, the flow remains symmetric about the plane halfway through the nozzle exits and the stagnation plane is located halfway between the two jets. When Re is increased past a critical value, asymmetric flow fields are obtained even when the momentum fluxes of the two opposed streams are equal. For unequal Re at the jet exits, when the fixed velocity (and the corresponding Reynolds number, Re₁) of one stream is low, the stagnation plane location, SPL, changes smoothly with the Re₂. For high enough Re₁, a hysteretic jump of SPL is observed. Particle Image Velocimetry and flow visualization demonstrate that within the hysteretic range, the two stable flow fields are anti-symmetric. The experimental setup is also studied with transient incompressible flow simulations using a spectral element solver. It is found that to accurately model the flow, we either need to extend the domain into the nozzles, or impose experimental velocity profiles at the nozzle exits. As in the experiments asymmetric flows are obtained past a critical Re. Finally, bifurcation analysis using a Newton-Picard method shows that the transition from symmetric to asymmetric flows results from the loss of stability of the symmetric flows at a pitchfork bifurcation.     

Development and evaluation of a numerical simulation approach to predict metal artifacts from passive implants in MRI

Objective

This study presents the development and evaluation of a numerical approach to simulate artifacts of metallic implants in an MR environment that can be applied to improve the testing procedure for MR image artifacts in medical implants according to ASTM F2119.

Methods

The numerical approach is validated by comparing simulations and measurements of two metallic test objects made of titanium and stainless steel at three different field strengths (1.5T, 3T and 7T). The difference in artifact size and shape between the simulated and measured artifacts were evaluated. A trend analysis of the artifact sizes in relation to the field strength was performed.

Results

The numerical simulation approach shows high similarity (between 75% and 84%) of simulated and measured artifact sizes of metallic implants. Simulated and measured artifact sizes in relation to the field strength resulted in a calculation guideline to determine and predict the artifact size at one field strength (e.g., 3T or 7T) based on a measurement that was obtained at another field strength only (e.g. 1.5T).

Conclusion

This work presents a novel tool to improve the MR image artifact testing procedure of passive medical implants. With the help of this tool detailed artifact investigations can be performed, which would otherwise only be possible with substantial measurement effort on different MRI systems and field strengths.

     

5-HT3 receptors augment neuronal, cholinergic contractions in guinea pig trachea

Localization of m3 mRNA, for the expression of the M3 muscarinic receptor, along the crypt-villus axis, was undertaken in rat jejunum by in situ hybridization. While enterocytes on the lower two-thirds of the villi showed the presence of m3 mRNA it was absent in the crypt enterocytes. This indicates that the final locus of muscarinically activated jejunal secretion is mediated by the M3 receptor on the enterocytes of the villi and not via the crypt cells.