Ammonia gas transport and reactions in unsaturated sediments: implications for use as an amendment to immobilize inorganic contaminants.

Use of gas-phase amendments for in situ remediation of inorganic contaminants in unsaturated sediments of the vadose zone may be advantageous, but there has been limited development and testing of gas remediation technologies. Treatment with ammonia gas has a potential for use in treating inorganic contaminants (such as uranium) because it induces a high pore-water pH, causing mineral dissolution and subsequent formation of stable precipitates that decrease the mobility of some contaminants. For field application of this treatment, further knowledge of ammonia transport in porous media and the geochemical reactions induced by ammonia treatment is needed. Laboratory studies were conducted to support calculations needed for field treatment design, to quantify advective and diffusive ammonia transport in unsaturated sediments, to evaluate inter-phase (gas/sediment/pore water) reactions, and to study reaction-induced pore-water chemistry changes as a function of ammonia delivery conditions, such as flow rate, gas concentration, and water content. Uranium-contaminated sediment was treated with ammonia gas to demonstrate U immobilization. Ammonia gas quickly partitions into sediment pore water and increases the pH up to 13.2. Injected ammonia gas advection front movement can be reasonably predicted by gas flow rate and equilibrium partitioning. The ammonia gas diffusion rate is a function of the water content in the sediment. Sodium, aluminum, and silica pore-water concentrations increase upon exposure to ammonia and then decline as aluminosilicates precipitate when the pH declines due to buffering. Up to 85% of the water-leachable U was immobilized by ammonia treatment.

Isolation of a muscarinic alkaloid with ocular hypotensive action from Trophis racemosa.

A muscarinic alkaloid with a quaternary nitrogen was isolated from Trophis racemosa. Aqueous solutions (0.5%-2%) of the chloride salt of the alkaloid produced dose-dependent reductions of intra-ocular pressure ranging from 6.6 +/- 0.7 mmHg to 15.7 +/- 0.3 mmHg, (p < 0. 001, n = 5) in dogs. Atropine (0.1 mL of a 1% solution) and pirenzepine at a non selective antagonist dose (0.1 mL of 0.5% solution) for M(1) and M(3) receptors blocked the reduction of intra-ocular pressure, but alpha-adrenoceptor blockade with phenoxybenzamine (0.1 mL of a 1% solution) did not block the reduction of intra-ocular pressure. On the isolated guinea-pig ileum and trachea, the alkaloid produced contractions which were inhibited by atropine (6 x 10(-7) M or 0.4 microg/mL) and by pirenzepine at a non-selective antagonist dose (3.1 x 10(-6) M or 1.3 microg/mL) for M(1) and M(3) receptors. But neither selective blockade of M(2) receptors with gallamine (1.7 x 10(-6) M or 1.5 microg/mL) nor selective blockade of M(1) receptors with pirenzepine (7 x 10(-9) M or 3 ng/mL) inhibited the alkaloid-induced contractions. There was also no inhibition of the alkaloid-induced contractions in the presence of ganglionic nicotinic receptor blockade with pentolinium (5.6 x 10(-7) M or 0.3 microg/mL) and hexamethonium (1.7 x 10(-6) M or 0.6 microg/mL), but nicotine-induced contractions were inhibited by these ganglionic blockers. These results suggest that a muscarinic alkaloid from Trophis racemosa produced ocular hypotension via M(3) receptor stimulation in dogs.

Pediatric oncology and hematology in Birmingham, England.

The hematology and oncology service at Birmingham Children's Hospital was established in the late 1960s and now is one of the largest in the United Kingdom. It provides comprehensive care for the entire range of childhood malignancies, coagulation disorders, and hemoglobinopathies and other hematological disorders, and undertakes bone marrow transplant and megatherapy/peripheral blood stem cell procedures. Research includes clinical trials of treatments of childhood cancers; molecular biology studies on leukemia, Hodgkin's disease, neuroblastoma, and sarconas; childhood cancer epidemiology, and geographical and racial incidence; and treatment of hemophilia and molecular investigation of coagulation disorders. These activities involve collaboration with local, national, and international research groups.

Enteral nutrition after bone marrow transplantation.

Nutritional insult after bone marrow transplantation (BMT) is complex and its nutritional management challenging. Enteral nutrition is cheaper and easier to provide than parenteral nutrition, but its tolerance and effectiveness in reversing nutritional depletion after BMT is poorly defined. Nutritional status, wellbeing, and nutritional biochemistry were prospectively assessed in 21 children (mean age 7.5 years; 14 boys) who received nasogastric feeding after BMT (mean duration 17 days) and in eight children (mean age 8 years, four boys) who refused enteral nutrition and who received dietetic advice only. Enteral nutrition was stopped prematurely in eight patients. Greater changes in weight and mid upper arm circumference were observed in the enteral nutrition group, while positive correlations were found between the duration of feeds and increase in weight and in mid upper arm circumference. Vomiting and diarrhoea had a similar incidence in the two groups, while fever and positive blood cultures occurred more frequently in the dietetic advice group. Diarrhoea occurring during enteral nutrition was not associated with fat malabsorption, while carbohydrate malabsorption was associated with rotavirus infection only. Enteral feeding did not, however, affect bone marrow recovery, hospital stay, general wellbeing, or serum albumin concentrations. Hypomagnesaemia, hypophosphataemia, zinc and selenium deficiency were common in both groups. In conclusion, enteral nutrition, when tolerated, is effective in limiting nutritional insult after BMT. With existing regimens nutritional biochemistry should be closely monitored in order to provide supplements when required.

Diagnosis and clinical associations of zinc depletion following bone marrow transplantation.

Following the emergence of biochemical zinc deficiency after bone marrow transplantation, the clinical value of plasma alkaline phosphatase activity as an early indicator of biochemical zinc depletion was investigated in this group of patients. Serial measurements of plasma zinc and alkaline phosphatase activities in 28 consecutive children (median age 8.7 years; 16 males) undergoing bone marrow transplantation were carried out and clinical associations recorded. A significant fall in plasma zinc occurred after the bone marrow transplant, and 19 children developed biochemical zinc deficiency (Zn < 11 mumol/l) at a median of 7 days following the transplant. Zinc depletion was more common in younger patients and in children with diarrhoea. A positive correlation was found between plasma zinc and alkaline phosphatase activities. Zinc depleted patients had more febrile episodes of longer duration and were more likely to have a positive blood culture. Haemopoetic recovery was not affected by zinc deficiency. Following zinc supplementation, alkaline phosphatase showed a significant increase. The sensitivity of a low alkaline phosphatase as a screening test for biochemical zinc deficiency was 83%, with a specificity of 86%. Low alkaline phosphatase activity following bone marrow transplant is an indication for zinc supplements.

Anemia in pregnancy.

In evaluating pregnant women with anemia, it is essential to do a complete history and physical examination, as well as a complete blood count with indices and a blood smear examination. Based on these findings, other tests such as ferritin and serum or red cell folate may be ordered. Because of the normal physiologic changes in pregnancy that affect the hematocrit, indices, and some other parameters, diagnosing true anemia, as well as the etiology of anemia, is challenging. Because of the increased nutritional requirements of the mother and fetus, the most common anemias are iron deficiency anemia and folate deficiency megaloblastic anemia. These anemias are more common in women who have inadequate diets and who are not receiving prenatal iron and folate supplements. Other less common causes of acquired anemia in pregnancy are aplastic anemia and hemolytic anemia associated with preeclampsia. In addition, congenital anemias such as sickle cell disease can impact on the health of the mother and fetus. Obviously, severe anemia has adverse effects on the mother and the fetus. There is also evidence that less severe anemia is associated with poor pregnancy outcome. The cause of this association has yet to be elucidated. It is important, however, to diagnose and treat anemia in pregnancy to provide for optimal health of the mother and infant.

Early treatment of Campylobacter jejuni enteritis.

The bacteriologic and clinical effects of early antibiotic treatment of Campylobacter jejuni enteritis were studied. Erythromycin rapidly eliminated C. jejuni from stools, whereas trimethoprim-sulfamethoxazole did not. Despite its bacteriologic effectiveness, erythromycin did not reduce the duration or severity of diarrhea, abdominal pain, or other symptoms.