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published_or_final_version / abstract / Clinical Psychology / Master / Master of Social Sciences

Currently, many methods are available for the analysis of drugs of abuse in urine but they all have their drawbacks. Thus, the purpose of this research was to overcome some of these drawbacks by developing multi-analyte detection systems based on sequential or spatial techniques and immunoassays. The first system was based on a spatial technique and involved a simple indirect competitive ELISA format. This produced relatively rapid multi-analyte dip-strip ELISAs for benzoylecgonine (BE), methadone (MET) and morphine (MOR). Various enzyme-labelled antibodies, substrates and filters were investigated. A multi-analyte dip-strip assay was developed based on cellulose nitrate filters, alkaline phosphatase labelled anti-mouse second antibody and nitro blue tetrazolium / 5-bromo-4-chloro-3- indoyl phosphate (NBT /BCIP) substrate. The resulting assays gave a simple 'yes/no' result when drug was present or absent from a sample at concentrations of 1.45 f,lg ml-I , 1.55 f,lg ml-I and 1.43 f,lg ml-I for BE, MET and MOR respectively. Limitations however were encountered that caused the concentrations to be above the accepted cutoff levels for these three drugs of abuse. The second system was based on a sequential technique and involved a flow-injection nnmunoassay (FIlA). Various monoclonal antibodies, fluorotracers and immobilisation methods were investigated. For morphine, a novel simple FIlA was developed which is based on competition between a mixture of a fluorescein derivative of the drug and morphine in flow over low affinity monoclonal morphine antibodies immobilised on a N-hydroxysuccinimidyl chloroformate activated agarose immunoreactor. With this system, a split peak profile (unbound and retarded fractions) was observed under isocratic conditions with the retarded peak disappearing and the unbound peak increasing in peak height/area as the concentration of morphine increased. Using a flow-rate of 0.5 ml min-I and a fluorescein derivative dilution of 1: 100, this assay had a sample throughput of 4 samples h-I and a detection limit of 14.1 f,lg ml- I . For a flow-rate of 1.6 ml min-I and a fluorescein derivative dilution of 1: 1 00,the assay had a sample throughput of 6 samples h-I and a detection limit of 10.9 J.!g mri. The origin of the phenomenon was investigated and revealed to be due to the low association rate of the drug tracer with the morphine antibody used and the near equivalence of the monoclonal antibody affinity for its respective tracer and drug. It was found that when these values are exceeded, the "split peak" phenomenon was not observed but the reagents could be used in conventional displacement flow injection fluoroimmunoassays as was demonstrated for benzoylecgonine and methadone.

The rising numbers of young drug abusers in Hong Kong have attracted much concern by the government. Unfortunately, there are few established studies that have been conducted to evaluate the effectiveness of the existing rehabilitation and treatment programs. The dearth of research in this area can compromise the potential for the improvement of current services and hinder the development of new intervention strategies. The present study aimed to help filling in this gap in the literature through the evaluation of Christian Zheng Sheng College, a school-based rehabilitation program. Across a year of observation, we documented the students’ improvements on a range of outcomes (i.e. self-efficacy, school engagement, civic responsibility, perceived social support and religious coping). We also examined whether the perceived quality of natural mentoring relationships established within Zheng Sheng were related to these changes. Across the four waves, the overall population displayed significant linear growths in all measured outcomes apart from civic responsibility and perceived social support. Results also revealed that the perceived closeness with an identified mentor in Zheng Sheng accounted for differential impact toward youth’s self-efficacy, civic responsibility and perceived social support. Implications of the findings were discussed in particular reference to other drug rehabilitation programs in Hong Kong. / published_or_final_version / Clinical Psychology / Master / Master of Social Sciences

The Enterobacter are often found in the feces of man and other warm blooded animals but have limited use as indicators of fecal contamination of foods and water since they are also often found as natural flora of non-fecal environments such as water and plants. This study proposes a method that may be useful for differentiating between fecal and non-fecal Enterobacter. Coliform bacteria associated with the human fecal environment often have a high incidence of multiple resistance to antibiotics. By determining multiple drug resistance and indexing Enterobacter in reference to their environmental source, it was discovered that isolates from human feces, raw sewage and certain foods demonstrated a higher index than isolates from rural soils, wild animal feces, cereal grains and other non-human environments. An index value greater than 0.2 indicated isolates from environments contaminated with human feces representing a high health risk while those isolates with an index of less than 0.2 came from relatively safe environments. Traditionally, the assessment of food borne health hazards is determined by measuring the quantity and kind of bacteria present. Drug resistance indexing will compliment these tests and aid in identifying serious bacterial contamination of foods. / Graduation date: 1981

No description available.

No description available.

No description available.

No description available.