Investigations into the source of two fungicides measured in the air for 24 hours following application to a cereal crop.

Airborne pesticides can be detected near to recently-treated arable fields for a period of days following the application. Identifying the source of such pesticides is important in developing predictive models for use in exposure and risk assessments. Previous work showed levels of pesticide in the air that were higher than expected for a low-vapour-pressure active ingredient, epoxiconazole, and comparable with an active ingredient of a significantly higher vapour pressure, fenpropidin. It was possible that the measured concentrations could be attributed to 'dust' particles emitted from the crop, either biological material contaminated with pesticide or solid dried deposits of active ingredient and other formulation components. A second experiment was therefore undertaken to measure airborne concentrations of the same active ingredients and to determine whether some or all of the measured airborne pesticide could be attributed to particles, using a Marple personal cascade impactor, which collects particles in the range 0.3 - 50 microm. Such samplers are not optimised to give good sampling efficiencies under the proposed field conditions, so some initial tests were undertaken in the Silsoe wind tunnel to assess its ability to sample particles in an air flow. In the subsequent field trial, a 192 m square plot in a commercially established winter cereal crop was sprayed with a tank mix of commercial formulations of epoxiconazole and fenpropidin. Measurements of airborne pesticides were made for 24 hours following the application with suction samplers attached to tenax tubes to evaluate vapour concentrations and with the cascade impactor to determine whether contaminated airborne particles were present. The concentrations of pesticide measured with the tenax tubes were significantly higher than the particulate component detected on the cascade impactor plates and it is therefore it was very unlikely that there was a significant contribution from pesticide-laden particles to the airborne concentration. Although it is clear that under these particular experimental conditions, airborne contaminated particles were not detected in significant quantities after the application, it is possible that this could occur under different circumstances, such as during pollen release or harvest.

Papillary thyroid carcinoma, parathyroid adenoma, and unexplained hypercalcitoninemia: an unusual presentation of multiple endocrine neoplasia type 2A?

Multiple endocrine neoplasia type 2 (MEN 2) is a rare syndrome of medullary thyroid carcinoma (MTC) with pheochromocytoma and/or primary hyperparathyroidism (PHP), usually due to multigland hyperplasia. MEN 2 is associated with several RET protooncogene mutations. A 61-year-old woman with a family history of RET-positive MTC presented with a solitary thyroid nodule. Fine-needle aspiration biopsy was suspicious for neoplasm. Biochemical studies revealed basal hypercalcitoninemia (116 pg/mL [normal <26]) and PHP (serum calcium, 10.9 mg/dL; intact PTH, 113.2 pg/mL [10.0-65.0]). Pheochromocytoma screening was negative. A provisional diagnosis of MEN 2 was made, but at surgery, a single parathyroid adenoma was resected and frozen sections of several lymph nodes revealed papillary thyroid carcinoma (PTC). A total thyroidectomy was performed. Final histological diagnosis was PTC and parathyroid adenoma with no evidence of MTC. Postoperatively, RET mutation testing was positive. The basal calcitonin (CT) fell to 25 pg/mL, but peaked at 935 (normal <105) after pentagastrin infusion, consistent with occult MTC. After radioiodine ablation, CT decreased further. Octreotide scanning was negative. Faced with PHP, a thyroid nodule, and a family history of MTC, clinicians tend to diagnose MEN 2. This patient had a single parathyroid adenoma and nonmedullary thyroid cancer, which the literature actually suggests to be an association more frequent than MEN 2. Yet, there remains compelling data in favor of occult MTC, leaving open the possibility of an MEN 2 variant with the rare association of PTC.

Pedicled osseous flaps.

Craniofacial skeletal defects are most optimally reconstructed with vascularized autogenous bone. There are two methods of achieving such a vascularized osseous reconstruction: microvascular bone transfers and pedicled osseous flaps. Although microvascular composite grafts allow a greater quantity and variety of bone to be moved to the reconstructive site, pedicled osseous flaps remain an excellent reconstructive option. Pedicled osseous flaps are not technically complex, result in minimal donor site morbidity, and demonstrate acceptable reliability in selected cases. This article reviews the realm of pedicled osseous flaps that can be used in craniofacial reconstruction. Although infrequently employed, these useful flaps should remain in the armamentarium of the head and neck surgeon.

Detoxification of liquid cultures of Bordetella pertussis by forced aeration at high pH.

Cultures of Bordetella pertussis cultivated in shake flasks were invariably highly toxic for mice, but cultures of the same strain grown in vortex-aerated vessels were nontoxic at the time of harvest. Results reported here indicate that toxin is present during the early log phase in vortex-aerated cultures, but is lost as the cultivation proceeds. The loss of toxicity is apparently due to denaturation of the toxin by the combined influence of vigorous aeration and elevated pH.

Appearance of mouse-lethal toxin in liquid cultures of Bordetella pertussis.

The mouse-lethal toxin present in liquid cultures of most smooth strains of Bordetella pertussis is known to originate in the cytoplasm of the organism but to be most lethal for mice when released into the supernatant fluid. It is also recognized that cell degeneration and lysis occur in liquid cultures during the stationary and decline phases of growth. For these reasons, it is generally believed that most of the toxicity demonstrable in liquid cultures at the time of harvest is released during the later stages of cultivation, when high alkalinity and aging of cells favor lysis. However, the results reported here have indicated that high levels of mouse-lethal toxicity arise during very early log phase and that the peak of toxicity is reached before the end of the log phase. No further increase in toxicity was observed during stationary and decline phases. The very early appearance of toxicity could not be explained by the presence in the inoculum of a proportion of dead and degenerating cells, and it is concluded that the toxin is produced mainly by actively growing cells. This was confirmed by tests on organisms growing in continuous culture. Electron-microscopic examination of cells from a very early log-phase culture revealed the presence of large numbers of small vesicles on the cell walls of about 5% of the population. It is suggested that these vesicles may be associated with the releases of toxin from living cells. It is concluded that no useful reduction in the toxicity of cultures would result from harvesting before the end of the log phase of growth.

Use of glutamic acid to supplement fluid medium for cultivation of Bordetella pertussis.

The amino acid consumption by Bordetella pertussis growing in broth containing casein hydrolysate was examined. Serine, proline, alanine, glycine, aspartate, and glutamate were rapidly consumed, in a manner which suggested that they supplied the energy requirements of the organism; exhaustion of the energy source appeared to be the main factor limiting the yield of cells. There was no correlation between the utilization of individual amino acids and the phase of growth; uptake appeared to depend only upon relative concentrations. Consumption of threonine, phenylalanine, histidine, leucine, and methionine was slight; consumption of valine and lysine was variable, and isoleucine was excreted. The addition of monosodium l-glutamate (3 mg/ml) to the broth in shaken flasks increased the cell yield by an average of 43.5%. It had no detectable adverse effect upon the agglutin-producing capacity, agglutinability in antisera versus smooth and rough growth phases, mouse-lethal toxicity, histamine-sensitizing factor potency, or intracerebral protective potency of the culture. Broth supplemented with monosodium l-glutamate has been used over a 2-year period to prepare experimental vaccines by both batch and continuous cultivation methods at controlled pH; the cell yields obtained from the supplemented broth have been up to 52% higher than those from the basal broth. The use of glutamate to replace a proportion of casein hydrolysate in the broth caused a reduction in the cell yield, an alteration in cell morphology, and reduction in the mouse-lethal toxicity, the histamine-sensitizing factor potency, and the intracerebral protective potency of the cells.

Effect of pertussis vaccination on the sensitivity of mice to insulin, bicarbonate, and CO2.

Prior pertussis vaccination increased the sensitivity of mice to intraperitoneal injections of insulin and of sodium bicarbonate, but it reduced their sensitivity to high levels of inhaled carbon dioxide.

Characterisation of extracellular polysaccharides from suspension cultures of members of the poaceae.

Microscopic examination of suspension- cultured cells of Phleum pratense L., Panicum miliaceum L., Phalarisaquatica L. and Oryza sativa L. showed that they were comprised of numerous root primordia. Polysaccharides secreted by these suspension cultures contained glycosyl linkages consistent with the presence of high proportions of root mucilage-like polysaccharides. In contrast, suspension-cultured cells of Hordeum vulgare L. contained mostly undifferentiated cells more typical of plant cells in suspension culture. The polysaccharides secreted by H. vulgare cultures contained mostly linkages consistent with the presence of glucuronoarabinoxylan. The soluble polymers secreted by cell-suspension cultures of Phleum pratense contained 70% carbohydrate, 14% protein and 6% inorganic material. The extracellular polysaccharides were separated into four fractions by anion-exchange chromatography using a gradient of imidazole-HCl at pH 7.0. From glycosyl-linkage analyses, five polysaccharides were identified: an arabinosylated xyloglucan (comprising 20% of the total polysaccharide), a glucomannan (6%), a type-II arabinogalactan (an arabinogalactan-protein; 7%), an acidic xylan (3%), and a root-slime-like polysaccharide, which contained features of type-II arabinogalactans and glucuronomannans (65%).