Thyroid-hormone therapy and thyroid cancer: a reassessment.

Experimental studies and clinical data have demonstrated that thyroid-cell proliferation is dependent on thyroid-stimulating hormone (TSH), thereby providing the rationale for TSH suppression as a treatment for differentiated thyroid cancer. Several reports have shown that hormone-suppressive treatment with the L-enantiomer of tetraiodothyronine (L-T(4)) benefits high-risk thyroid cancer patients by decreasing progression and recurrence rates, and cancer-related mortality. Evidence suggests, however, that complex regulatory mechanisms (including both TSH-dependent and TSH-independent pathways) are involved in thyroid-cell regulation. Indeed, no significant improvement has been obtained by suppressing TSH in patients with low-risk thyroid cancer. Moreover, TSH suppression implies a state of subclinical thyrotoxicosis. In low-risk patients, the goal of L-T(4) treatment is therefore to obtain a TSH level in the normal range (0.5-2.5 mU/l). Only selected patients with high-risk papillary and follicular thyroid cancer require long-term TSH-suppressive doses of L-T(4). In these patients, careful monitoring is necessary to avoid undesirable effects on bone and heart

Cooling of rocket thrust chambers with liquid oxygen

Rocket engines using high pressure liquid oxygen (LOX) and kerosene (RP-1) as the propellants have been considered for future launch vehicle propulsion. Generally, in regeneratively cooled engines, the fuel is used to cool the combustion chamber. However, hydrocarbons such as RP-1 are limited in their cooling capability at high temperatures and pressures. Therefore, LOX is being considered as an alternative coolant. However, there has been concern as to the effect on the integrity of the chamber liner if oxygen leaks into the combustion zone through fatigue cracks that may develop between the cooling passages and the hot-gas side wall. To address this concern, an investigation was previously conducted with simulated fatigue cracks upstream of the thrust chamber throat. When these chambers were tested, an unexpected melting in the throat region developed which was not in line with the simulated fatigue cracks. The current experimental program was conducted in order to determine the cause for the failure in the earlier thrust chambers and to further investigate the effects of cracks in the thrust chamber liner upstream of the throat. The thrust chambers were tested at oxygen-to-fuel mixture ratios from 1.5 to 2.86 at a nominal chamber pressure of 8.6 MPa. As a result of the test series, the reason for the failure occurring in the earlier work was determined to be injector anomalies. The LOX leaking through the simulated fatigue cracks did not affect the integrity of the chambers

Spontaneous Goiter and Cancer of the Thyroid in Animals

Author Institution: Department of Pathology, College of Medicine, The Ohio State University, Columbus 1

Corporal Punishment in Public Schools: Constitutional Challenge After Ingraham v. Wright

Corporal punishment has been employed to maintain discipline and order in American schools since the colonial period.\u27 During that era, the practice was not restricted to the classroom: corporal punishment was the generally accepted mode of correction for practically every civil and criminal offense. Attitudes toward correction did not begin to change until after the American Revolution. Since then, corporal punishment has been steadily discarded as a method of correction in both prisons and the military. Despite discontinuance in these areas, corporal punishment remains a well-established facet of the American educational process. Only a few states and municipalities have legislative prohibitions against the use of this disciplinary method in their public schools, and the courts consistently have rejected constitutional challenges to provisions authorizing its use... As representative bodies,legislatures theoretically enact and amend the laws as changes in societal attitudes dictate. Resolution of the question whether corporal punishment should be used as a means of disciplining schoolchildren requires basic value judgments that courts are ill-equipped to make. Nonetheless, to the extent that a form of punishment has constitutional implications, the judicial function must be exercised. Challenges to the constitutionality of corporal punishment have commonly relied upon four theories: cruel and unusual punishment,the parental rights doctrine, procedural due process, and substantive due process. The first three issues have been resolved formally by the Supreme Court of the United States. The substantive due process issue, however, has been determined conclusively only in the Fifth Circuit. This Note will first review these four issues as they have confronted the lower courts and then will analyze Ingraham v. Wright, in which the Supreme Court ruled on the cruel and unusual punishment and procedural due process issues. Discussion will center on the substantive due process issue, suggesting the feasibility of a suit challenging the practice as administered in a given instance

Réseaux trophiques et production piscicole en étangs fertilisés (Dordogne, France)

Des séries de données (physicochimie, plancton, poisson) collectées pendant deux saisons consécutives sur deux groupes d'étangs de pisciculture de Dordogne (Sud-ouest de la France) ont été analysées statistiquement (analyses en composantes principales ACP, analyse des correspondances multiples ACM, tris croisés). Des liens significatifs entre les différents constituants de la chaîne trophique ont été identifiés, et les facteurs clés de la production piscicole mis en évidence. En début de saison, une régulation ascendante oriente la composition et l'abondance de la flore algale, suivant les concentrations de N et PO4 et leurs proportions relatives. L'abondance du zooplancton filtreur est liée à la fois aux ressources trophiques disponibles (cellules algales aisément ingérables) et à la pression de prédation qu'il subit de la part des juvéniles de poissons. La production piscicole de gardon (Rutilus rutilus) et de tanche (Tinca tinca) est plus faible si ces espèces sont associées (compétition alimentaire interspécifique chez les juvéniles) ou produites en présence d'un carnivore. En contre-partie d'une production piscicole plus faible, la stabilité de la structure du réseau trophique est accrue. Les concentrations en P-PO4, la quantité de grands Crustacés planctoniques et une densité de poissons adaptée aux capacités du milieu constituent les facteurs clés de la production piscicole finale.The main parameters (physicochemistry, plankton, fish) of two sets of fish ponds (8 and 9 ponds respectively; area between 0.2 and 1.2 ha; mean depth: 1.5 m) located in south-west of France were monitored during two consecutive seasons (1995, 1996). The benthic macroinvertebrates and the microbial loop were not taken into account for these field studies. No macrophytes were growing into the studied ponds. The multivariate analyses of the two yearly data bases provided informations on the strength of the various links among and between the successive compartments of the food web (physicochemistry of water, phytoplankton, zooplankton and fish) and identified the bottlenecks of the food web to the fish production.Integrated water samples were collected bimonthly (from May to September) for field measurements (T°, pH, dissolved O2, Secchi disc transparency, conductivity) and laboratory analyses ([N.NH4], [N.NO2], [N.NO3], [ortho-P], [Ca] using a HACH spectrophotometer). The groups of planktonic algae (Diatoms, Desmidieae, Dinophyceae, Chlorococcales and Volvocales, Euglenophyceae, Cyanobacteriae) were identified and classified in three categories (dominant, present, rare). Rotifers, Cladocerans and Copepods were numbered (N/litre) into two size classes (large or small, with a threshold at 400 µm). One hundred liters of pond water were filtered through a plankton net (mesh size: 80 µm) and the volume of sedimented zooplankters measured as zooplankton biovolume (mL/100 liters). The total numbers of fish stocked and collected are noted (weight and number of fish/species; age classes). Working on private production ponds, we were not allowed to make catches for stomach contents studies.The data from each season were analysed through PCA, MCA, crosstabs (STATBOX software from GRIMMER); for each species of fish a ratio was computed between the biomass of the collected juveniles and the biomass of the stocked breeders. In the studied fish ponds like in other eutrophic bodies of water, the densities of the planktonic organisms follow a bimodal evolution, with high numbers at the end of spring (June) and the end of summer (August), separated by a phase of more transparent water. During the first phase, Daphnia and large Cladocerans are predominant with Chlorophyceae, replaced later in the season by species of smaller size and shorter life cycle (Bosmina, Ceriodaphnia, Cyclops), associated with Cyanobacteriae, at a time where predation by fish is more intense as their biomass increase. In spring, different algal communities develop with density depending on the initial concentrations of inorganic N and PO4 and the PO4 /N ratio. If the available dissolved N and P are infra-optimal, mixotroph algae (Chrysophyceae, Dinophyceae) and Rotifers predominate. When [N] is not limiting (N/P between 4/1 and 10/1), Chlorophyceae become predominant, but if PO4 is in relative excess, they are replaced by Cyanobacteria. The abundance of grazing Cladocerans is linked to the capacity of the available algal cells to be ingested. Cyanobacteria can already become predominant in May because of the selective grazing by Cladocerans on more readily ingestible phytoplankton taxa. Links among groups of zooplankton are evidenced: small grazers (Rotifers, Cladocera 2 mL/100 L), a water transparency between 0.30 and 0.70 m and are related to a shift from small size species ( 400 µm). In spring numerous small zooplankters facilitate the survival of the fish fry, whose growth is later ensured by high densities of larger Crustaceans.From the fish production data, the ratios between the biomass of collected juveniles and the biomass of stocked breeders were compared under different rearing conditions for the various species. Roach Rutilus rutilus, tench Tinca tinca and gudgeon Gobio gobio have similar production potentials when reared separately (juveniles production in kg is 5 to 7 times the biomass of the breeders). When roach and tench are reared together under the same conditions, the ratio is divided by 2 for each species, but the total net production of fish remains at the same level (500-600 kg/ha). This shows that there is a strong feeding competition on zooplankton between the juveniles of roach and tench. In opposition, there is little feeding competition between roach and gudgeon. When the two benthic species are associated, tench strongly dominates the gudgeon. The addition of a carnivorous species to the association of roach + tench reduces the final total production by 250-300 kg/ha. Between 30 and 40 kg of carnivorous fish (Esox lucius or Stizostedion lucioperca) are produced at the expense of the equivalent of a final biomass of 200 kg/ha of young Cyprinids. The pressure of predation from these two top consumers is 2 to 3 times less intense compared to the predation exerted by the large-mouth bass Micropterus salmoides.As the basic food for juvenile fish, the zooplankton can be considered here as the key element of the food web, between the bottom-up (production) and top-down (predation) effects. The ortho-phosphate concentration is the limiting factor for the ascending regulation of the food web, and the amount of initially stocked fish regulates the top-down effects. The maximum net final fish production reached about 800 kg/ha with roach alone, or in association with tench. In such cases, Cyanobacteria were dominant in the pond with the presence of Chlorophyceae. The low density of zooplankton and the sub-optimal dissolved oxygen concentrations during the day seem to indicate that at such production level, the food chain is near to collapse

Functional characterization of human thyroid tissue with immunohistochemistry

Immunohistochemistry provides insights in the expression of functional proteins and of their localization in normal thyroid tissue and in thyroid diseases. In hyperfunctional thyroid tissues, staining for sodium/iodide symporter (NIS), pendrin, thyroid peroxidase (TPO), and thyroglobulin (Tg) is increased. In hypofunctioning thyroid tissues, NIS staining is markedly decreased; in benign hypofunctioning adenomas, the expression of the other functional proteins is unmodified or slightly decreased, whereas their expression is profoundly decreased or absent in differentiated thyroid carcinoma