PubMed Health⌕ Search

Biomedical subjects

S F Kwok

Publications and source records attributed to S F Kwok.

30 records · Page 2Linked to original sources
PubMed1986

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.

Asia↗
PubMed1986

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.

Dermatitis, Contact↗
PubMed1985

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.

Aged↗
PubMed1984

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.

Adult↗
PubMed1984

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.

Acute Kidney Injury↗
PubMed1982

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.

Air Pollutants↗
PubMed1981

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.

Asia, Southeastern↗
PubMedDate not supplied

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.

Chromates↗