Arabidopsis ethylene-response gene ETR1: similarity of product to two-component regulators.

Ethylene behaves as a hormone in plants, regulating such aspects of growth and development as fruit ripening, flower senescence, and abscission. Ethylene insensitivity is conferred by dominant mutations in the ETR1 gene early in the ethylene signal transduction pathway of Arabidopsis thaliana. The ETR1 gene was cloned by the method of chromosome walking. Each of the four known etr1 mutant alleles contains a missense mutation near the amino terminus of the predicted protein. Although the sequence of the amino-terminal half of the deduced ETR1 protein appears to be novel, the carboxyl-terminal half is similar in sequence to both components of the prokaryotic family of signal transducers known as the two-component systems. Thus, an early step in ethylene signal transduction in plants may involve transfer of phosphate as in prokaryotic two-component systems. The dominant etr1-1 mutant gene conferred ethylene insensitivity to wild-type Arabidopsis plants when introduced by transformation.

The cellular level of PR500, a protein complex related to the 19S regulatory particle of the proteasome, is regulated in response to stresses in plants.

In Arabidopsis seedlings and cauliflower florets, Rpn6 (a proteasome non-ATPase regulatory subunit) was found in two distinct protein complexes of approximately 800 and 500 kDa, respectively. The large complex likely represents the proteasome 19S regulator particle (RP) because it displays the expected subunit composition and all characteristics. The small complex, designated PR500, shares at least three subunits with the "lid" subcomplex of 19S RP and is loosely associated with an hsp70 protein. In Arabidopsis COP9 signalosome mutants, PR500 was specifically absent or reduced to an extent that correlates with the severity of the mutations. Furthermore, PR500 was also diminished in response to potential protein-misfolding stresses caused by the heat shock and canavanine treatment. Immunofluorescence studies suggest that PR500 has a distinct localization pattern and is enriched in specific nuclear foci. We propose that PR500 may be evolved in higher plants to cope with the frequently encountered environmental stresses.

Characterization of two subunits of Arabidopsis 19S proteasome regulatory complex and its possible interaction with the COP9 complex.

The nuclear localized, multi-subunit COP9 complex (or COP9 signalosome) is a key developmental modulator involved in repression of photomorphogenesis. In an effort to further define the molecular actions of the COP9 complex, a yeast two hybrid interactive screen was undertaken to identify proteins that could directly interact with one subunit of this complex, namely FUS6/COP11. This screen identified one specific interactive protein, AtS9, that is likely the Arabidopsis non-ATPase S9 (subunit 9) of the 19S regulatory complex from the 26S proteasome. AtS9 specifically interacts with FUS6/COP11 via the C-terminal domain of FUS6/COP11, which is distinct from the N-terminal domain necessary for FUS6/COP11 to interact with itself. As anticipated, AtS9 is not a member of the COP9 complex, but tightly associates with an ATPase subunit of the Arabidopsis 19S proteasome regulatory complex, AtS6A. Since all three proteins, FUS6/COP11, AtS9, and AtS6A, are present as complexed forms in vivo, the observed interaction implies that the COP9 complex may directly interact with the 19S regulatory complex of the 26S proteasome or other potential AtS9-containing complex. This notion is consistent with the parallel tissue-specific expression patterns and the similar, predominantly nuclear localization of both the COP9 complex and the AtS9 protein.

Study on the health hazards of scrap metal cutters.

Scrap metal cutters seemed to be left out in most preventive programmes as the workers were mainly contract workers. The health hazards of scrap metal cutting in 54 workers from a foundry and a ship breaking plant were evaluated. Environmental sampling showed lead levels ranging from 0.02 to 0.57 mg/m3 (threshold limit values is 0.15 mg/m3). Exposure to lead came mainly from the paint coat of the metals cut. Metal fume fever was not reported although their main complaints were cough and rhinitis. Skin burns at all stages of healing and residual scars were seen over hands, forearms and thighs. 96% of the cutters had blood lead levels exceeding 40 micrograms/100 ml with 10 workers exceeding 70 micrograms/100 ml. None had clinical evidence of lead poisoning. The study showed that scrap metal cutting is a hazardous industry associated with significant lead exposure. With proper medical supervision, the blood lead levels of this group of workers decreased illustrating the importance of identifying the hazard and implementing appropriate medical surveillance programmes.

Respiratory function in cadmium battery workers--a follow-up study.

The lung function status of workers in a cadmium-nickel battery factory was re-examined 3 years after an initial study which showed a mild restrictive effect. During this period, further measures were taken to reduce the cadmium exposure. Of the 44 'original' cadmium-exposed workers, 17 were still exposed to cadmium. Another 13 were transferred to non-cadmium work at least 6 months and 14 left the company at least 1 year before the present study. Blood and urine cadmium concentrations were considerably lower than previously, consistent with the decreased cadmium-in-air levels. The total lung capacity increased both in the workers who were still exposed to cadmium and those who ceased exposure. The latter group also had increased vital capacity and forced expiratory volume in one second. The prevalence of respiratory symptoms decreased particularly in the workers who were no longer exposed to cadmium.

Study on workers exposed to cadmium in alkaline storage battery manufacturing and PVC compounding.

The extent of cadmium exposure was studied in a cadmium-nickel battery factory and 8 PVC factories using cadmium stabilisers in the compounding of PVC. A total of 101 cadmium-exposed workers and 21 control subjects matched by sex, age, ethnic group and smoking history was investigated. Blood and urine cadmium levels were considerably elevated in the battery workers but were not raised in the PVC workers. These findings were consistent with the results of cadmium-in-air assessments. Among the female battery workers, urine cadmium excretion increased significantly with employment time. There was good correlation between blood and urine cadmium levels among the female subjects. A significant association between blood cadmium levels and prevalence of chest pain was also noted among the females. No low molecular weight proteinuria was detected, but two female battery workers had slight albuminuria and one male PVC worker had glucosuria but had abnormal GTT results.

Five cases of arsine poisoning.

Arsine is one of the most potent haemolytic agents found in industry. Four workers presented with abdominal pain, jaundice and passing tea-coloured urine. A fifth worker also passed dark urine but had no other symptoms. Investigation revealed that all five workers were from a tin smelting plant where they were involved in mixing tin ore with dross. They were exposed to arsine gas after mixing a particularly large quantity of dross with tin ore which was wet because of rain. Three of the cases developed renal impairment and also a mild sensory neuropathy. All survived with proper management in hospital which included exchange blood transfusions, and peritoneal dialysis where indicated. Prevention of such poisoning includes keeping dross away from all moisture, good ventilation in work areas, and adding dross directly to the furnace.

The influence of temperature on the concentration homogeneity of patch test materials.

The concentration homogeneity of nickel sulphate 4.8% pet. and potassium dichromate 0.5% pet. in patch test materials appeared to become less homogeneous if stored at room temperature compared storage at 4 degrees C, after 2 months. The coefficient of variation of concentration for nickel sulphate after storage at 4 degrees C was 3.0883%, and at room temperature 25.3098%. The coefficient of variation for potassium dichromate after storage at 4 degrees C was 4.6324% and at room temperature 9.6334%. This indicates that patch test materials containing nickel sulphate and potassium dichromate should be kept refrigerated in the tropics.

A simple method of qualitative analysis for musk ambrette, musk ketone and musk xylene in cologne.

Musk ambrette has become one of the commonest photosensitizers in many countries and is the cause of persistent light reactions in many patients. A simple method is presented for qualitative analysis for musk ambrette and other nitromusks in colognes using thin-layer chromatography with toluene as carrier solvent and visualization under UVL. It is useful for identifying such colognes so that proper recommendations can be given to patients sensitive to musk ambrette. 14 of 32 men's colognes, analysed by TLC and confirmed on GC/MS, were found to contain musk ambrette, the concentration varying from 0.02 to 0.39% w/v.

Differentiation and comparison of raw, prepared and dross opium.

Comparative studies involving colour tests, thin-layer chromatography (TLC) and gas-liquid chromatography (GLC) were made on raw, prepared and dross opium with a view to establishing means for their differentiation. Analysis of a large number of samples found in south-east Asia showed the typical patterns and results to be quite distinctive in the qualitative and quantitative aspects. The relative proportions of the major alkaloids in the two chromatographic systems were used to advantage in the comparison. Prepared opium was found to have a characteristic yellow fluorescent spot on the TLC plate when viewed under long-wavelength ultraviolet light. No positive marker was found for dross opium, its unusual features being the relatively high morphine and codeine content and the absence of narcotine, meconic acid and especially thebaine. Most of the prepared opium samples were found to have been made from a mixture of raw and dross opium. The modified hallucinogen reagent of Maunder was found to be a suitable alternative chromogenic spray in the TLC analysis.

Photosensitivity associated with carprofen (Imadyl).

Photodermatitis from Carprofen in 3 patients was reported. The absorbance spectrum of Carprofen revealed maximum absorbance at UVB range. The clinical presentation in the 3 patients suggested that a phototoxic mechanism may be responsible.

Cobalt and nickel content of Asian cements.

The total cobalt and nickel concentration of 11 brands of Asian cement ranged from 8.1 to 14.2 micrograms/g and 14.9 to 28.5 micrograms/g, respectively. These metals exist mainly as insoluble salts; the water-soluble concentration of cobalt and nickel in the cements ranged from 0.39 to 0.65 micrograms/g and from 0-1.2 micrograms/g, respectively. 1.5% (4/272) of construction workers in a prefabrication construction factory had cobalt sensitivity. All had allergic contact dermatitis from chromate in cement. No worker had isolated cobalt sensitivity and cement dermatitis. It appeared that sensitization to cobalt in cement occurs only secondarily to an existing cement dermatitis. 1.8% (5/272) workers had nickel sensitivity: 2 with allergic contact dermatitis to nickel in their watches, 2 were asymptomatic and 1 had allergic contact dermatitis to chromate and cobalt in cement. The low prevalence of cobalt and nickel sensitivity from cement was probably related to the low concentration of soluble cobalt and nickel salts in the cement. However, these insoluble salts can form soluble complexes with body fluids on eczematous skin and sensitize the skin.

Cross sensitivity in colour developers.

Colour developers are widely used and contact dermatitis and lichen planus-like eruptions from them are well-known. As a result of automation, there have been few recent reports of contact dermatitis from colour developers. We describe here 4 cases of dermatoses from Kodak CD4 colour developer and study their cross sensitivity to other colour developers and PPD. Attempts were made to determine the purity of the patch test allergens to ensure that cross sensitivity was not the result of contamination and decomposition of the allergens.

Chromate allergy: total chromium and hexavalent chromate in the air.

This is a study on atmospheric concentration of total chromium and hexavalent chromate and its role in chromate sensitivity. Air concentration of total chromium and hexavalent chromate in a construction factory, a busy city area, a suburban area, a residential area, and a heavy industrial area were measured by air sampling pumps. Hexavalent chromate was not detected in any sampled areas. Two (concreting areas) of 8 locations in the construction factory had total chromium of 0.2 and 2.3 micrograms/m3 in the atmosphere. It appeared that the atmospheric concentration of total chromium and hexavalent chromate was negligible. These findings indicate that unexplained chromate sensitivity, as so often seen in patients attending a contact dermatitis clinic, is not attributable to exposure to hexavalent chromate in the air.