The morphological development of the proventriculus of Dandarawi chick: Light and electron microscopical studies.

This study was carried out on 40 chick embryos collected from incubated eggs of Dandarawi chicken (Gallus gallus domesticus) on the 5th to 19th incubation day (27 to 45 Hamburger and Hamilton, H&H stages). In addition, 15 chicks were collected on the day of hatching (stage 46 H&H), one week and two weeks post-hatching to demonstrate the histological, histochemical, and electron microscopic developmental changes of the proventriculus (of the digestive tract). Histologically, the proventriculus was observed as a narrow tube at 27 H&H stage. It was lined by pseudostratified columnar epithelium through 27-39 H&H stages and from the stage 43 till post-hatching, it was lined by simple columnar epithelium. The Lamina muscularis mucosa could be identified at stage 43. The proventricular glands were detected firstly at stage 31 and branching at stage 35. Histochemically, the surface epithelium and proventricular glands reacted positively to PAS, alcian blue and bromophenol blue from stage 31 till maturity. The glands displayed an apocrine mode of secretion at stage 39 and their cytoplasm contained abundant mitochondria, RER, secretory granules, and lipid droplets. Enteroendocrine cells could be observed among the glandular and surface epithelium at stage 45 H&H. The interstitial tissue contained fibroblasts and telocytes. The telocytes were firstly detected at stage 35 H&H and composed of a cell body and two long cell processes called telopodes. The tunica muscularis differentiated into three layers of smooth muscle fibers at stage 37 H&H. The cellular and stromal organizations of the proventriculus and their relations to the development and function were discussed.

[Late cervicodorsal metastasis of thyroid adenocarcinoma treated by anterior cervicotomy]. / Métastase cervico-dorsale tardive d'un adénocarcinome thyroïdien opérée par cervicotomie antérieure.

Metastasis from a thyroid adenocarcinoma is a rare entity with high mortality. We describe an unusual case in a woman displaying tetraparesis due to a late cervico-dorsal metastasis operated on via a simple anterior cervicotomy. Outcome was good at eighteen months follow-up. The histological diagnosis was follicular adenocarcinoma. The development of a vertebral metastasis from a thyroid adenocarcinoma 11 years after the treatment of the primitive cancer is rare. The anterior cervico-dorsal location in this patient required decompression via an anterior approach. Surgical treatment of the tumor and spinal stabilization were possible via a simple anterior cervicotomy which allowed adequate access to the third thoracic vertebra, without sternotomy or thoracotomy.

Correlation clusters in the accumulation of metals in human scalp hair: effects of age, community of residence, and abundances of metals in air and water supplies.

Scalp hair samples taken from 122 children and 27 adults from three native Indian villages in northern Alberta, Canada were analyzed for 32 metals, in an attempt to trace industrial pollution into the human population. One of the villages has been exposed since 1967 to increased levels of several metals due to its proximity to the world's first two oil sands petroleum extraction plants (Suncor and Syncrude), which release large amounts of metals into the environment. Metal-enriched particulates are emitted at a rate of 547-780 kg h-1 for Suncor, and 713-1067 kg h-1 for Syncrude. To test the hypothesis that hair content reflected accumulation of environmental metals, water and aerometric samples were collected and analyzed for their metal content. These analyses demonstrated that elevated levels of nine metals in hair from children in one of the control villages (Garden River) are (with the exception of Al) correlated with increased levels of metals in water and air. Moreover, increased levels of Cu, but lowest levels of all other metals were found in hair and environmental samples from one control village (Fort Chipewyan). Correlation matrices for metals in the hair samples revealed three sets of highly intercorrelated metals ('correlation clusters'): (i) Pb/Cd; (ii) Al/V/Fe; (iii) Ca/Mg/Sr/Ba. These groups of metals were significantly intercorrelated (r greater than 0.6, p less than 0.001) in the total population, and in both children and adults, or both males and females, as well as when the population was compared according to community of residence. The robustness of the clusters is particularly noteworthy in view of large differences in the proportions and absolute amounts of the various metals in hair from children in the three villages. Plots of metal levels in hair as a function of age of subject reveal a dramatic decrease in concentrations of Al, V, and Fe during the first years of life. The high levels of Al and V in hair from very young children may reveal a lower selectivity in metal absorption, and a higher risk of toxicity during a period of rapid growth when need for nutritionally essential metals is particularly high.

The effects of salbutamol on pulmonary function in cyclists exposed to ozone: a pilot study.

In order to determine the effects of an inhaled bronchodilator on the acute effects of ozone exposure on competitive cyclists, three subjects exercised on a stationary cycle ergometer for one hour in 0.34 +/- 0.02 ppm ozone, 29.8 +/- 0.3 degrees C. and 36.5 +/- 0.5% relative humidity under three experimental conditions. The initial test involved no pre-medication and served as a control. Using a double blind protocol the subjects were either given a placebo or salbutamol (200 micrograms via aerosol) prior to the second and third exposures. Pre- and post-exercise pulmonary function tests demonstrated a reduction in forced vital capacity (FVC) and forced expiratory volume in one second (FEV1), however, the magnitude of this reduction was not changed by the administration of salbutamol. These data suggest that pre-treatment with salbutamol is ineffective in reducing or eliminating pulmonary discomfort or respiratory dysfunction.

Trace metals in scalp hair of children and adults in three Alberta Indian villages.

This study examined trace metal levels in scalp hair taken from 122 children and 27 adult residents of three small northern Alberta (Canada) Indian villages, one of which is situated close to the world's first tar sands oil extraction plants. The three communities studied were: Fort McKay (the exposed village), Fort Chipewyan (also in the tar sands ecosystem but distant from the plants), and Garden River (not in the tar sands ecosystem). Inductively coupled argon plasma emission spectroscopy was used to determine hair sample metal content. Nineteen metals were included in data analysis. Children from Fort McKay had the highest average hair lead, cadmium and nickel levels. Chromium levels were approximately equal in hair from Fort McKay and Garden River children, and significantly elevated above levels found in the hair of Fort Chipewyan children. Children from Garden River showed highest hair levels of eight metals: vanadium, aluminum, iron, manganese, barium, zinc, magnesium and calcium. Fort Chipewyan children had the highest hair levels of copper, but the lowest levels of all other metals. Among adults, hair lead, nickel and cadmium levels were highest in Fort McKay residents, while phosphorous and vanadium were highest in hair from Garden River residents. Bioaccumulation of lead, cadmium, nickel and chromium in hair from Fort McKay residents may be related to exposure to extraction plant pollution. Plant stack emissions are known to contain appreciable amounts of lead, nickel and chromium. Spills into the Athabasca River, until recently the source of Fort McKay drinking water, have been reported from plant wastewater holding ponds, known to contain elevated levels of lead, nickel and cadmium. An increased number of significant metal-metal correlations in hair metal levels for Fort McKay children suggests a richer source of multiple metal exposure, relative to children in the other two communities.

Absorption, deposition and distribution of dietary aluminium in immature rats: effects of dietary vitamin D3 and food-borne chelating agent.

We report the levels of aluminium, calcium and potassium in selected tissues of growing rats administered dietary or subcutaneous aluminium, and also the effect of dietary aluminium in combination with cholecalciferol, or with lactose plus a dietary chelating agent. Dietary aluminium decreased the growth rate of normal rats and increased the deposition of aluminium in the tissues. Animals given lactose with a dietary chelator showed a 17 - 100% increase in brain, heart, and muscle aluminium concentration in comparison with those fed aluminium alone. Animals fed both aluminium with cholecalciferol also showed increased levels (12-39%) of aluminium, chiefly in muscle and heart in comparison with those fed aluminium alone. Aluminium deposition was correlated positively with Ca2+ and K+ levels among each of these tissues. We conclude that in normal growing rats aluminium deposition is increased in heart and muscle in the presence of vitamin D3 and in brain, heart and muscle in the presence of lactose and a dietary chelating agent.