Search PubMed⌕ Search

Biomedical subjects

L Thacker

Publications and source records attributed to L Thacker.

28 records · Page 2Linked to original sources
PubMed1976

Conjugation methods in immunofluorescence.

We have described methods of labeling antibody preparations with FITC, TMRI, and RBI. The degree of labeling with FITC can be precisely controlled by using well-defined conjugation procedures and FITC of a known degree of purity. Our experience shows that relatively high F/P ratios of the order of 20 to 25 mug/mg are desirable for antibacterial conjugates. Many commercial preparations of rhodamine isothiocyanate are of very poor quality and are unsatisfactory for use in conjugate preparation. Therefore, one should analyze the rhodamine isothiocyanate product before preparing immune conjugates. Our experience indicates that very satisfactory conjugates of immune IgG or pure antibody can be prepared with TMRI of about 60% purity by using a dye-protein ratio of 20 mug/mg. The optimal dye-IgG ratio for labeling with RBI appears to be about two times that for labeling with TMRI because of the lower specific absorbance and fluorescence emission of RBI. Rhodamine conjugates may be preferred to FITC conjugates in certain situations where tissue autofluorescence interferes with the observation of the yellow-green emission of FITC. Furthermore, mixed rhodamine and FITC conjugates of different specificity can be used to great advantage in double-staining techniques that allow simultaneous screening for two antigenically different organisms on a single microscope slide.

Fluoresceins↗
PubMed1976

Improvement in specificity of immunofluorescent reagents for identifying Streptococcus mutans by DEAE-cellulose-bacterial cell column immunosorption methods.

We have described a new method for preparing bacterial cell columns, in which DEAE-cellulose is used as the cell support material. The columns can be used to isolate pure antibody or to remove cross-reacting antibodies from immune IgG. The columns are remarkable stable, can be scaled up to any desired dimensions, and should be suitable for large-scale production of highly specific serological reagents. The method is practical for obtaining serotype-specific and polyvalent IF reagents for identifying S. mutans organisms. However, the method could also be used as a tool for sophisticated studies of antigenic relationships that exist among these and other taxonomic groups of microorganisms.

Antibodies, Bacterial↗
PubMed1974

In vitro production of N-nitrosodimethylamine and other amines by proteus species.

N-nitrosodimethylamine, a potent carcinogen, was produced by three strains each of Proteus mirabilis, P. morganii, and P. rettgeri, but not by three strains of P. vulgaris grown under the same conditions. Many of the alkaline-extractable volatile metabolites elaborated by these organisms are the same, but there are some qualitative and quantitative differences among species. Representative gas-liquid chromatographic profiles of the four species are presented, and the significance of the differences is discussed. Primary emphasis, however, is given to the importance of the production of N-nitrosodimethylamine by these microorganisms and the conditions under which it is produced.

Anhydrides↗
PubMedDate not supplied

On-site evaluation of bus drivers with coronary heart disease.

BACKGROUND: Bus drivers with ischemic heart disease have been denied normal employment, although they satisfy Canadian Cardiovascular Society (CCS) Guidelines. To show the safety of their reemployment, we compared their responses when driving buses with those seen during graded exercise testing. METHODS: Twenty-two male city bus drivers, aged 48.1 +/- 5.6 years (19 had a myocardial infarction, 2 had coronary artery bypass graft, 1 had documented ischemic heart disease) were referred for work evaluation. After a CCS cardiopulmonary exercise test, they were accompanied by a physician and a therapist/technician on a normal shift. Note was kept of symptoms, signs, electrocardiogram (telemetry), blood pressure (ambulatory recording unit), and Borg rating of effort throughout. RESULTS: Average values for peak heart rate (101 +/- 12.5 versus 148.2 +/- 17.2 beats/min), peak systolic pressure (150.0 +/- 20.8 versus 198.9 +/- 25.7 mm Hg), peak rate-pressure product (15,259 +/- 3,369 versus 29,500 +/- 5,283 units), peak Borg RPE (9.9 +/- 1.4 versus 17.4 +/- 3.0 units), and peak ST-segmental depression (-0.03 +/- 0.07 versus -0.07 +/- 0.09 mV) during the shift were only about a half of average values reached during the graded stress test. Moreover, peak values were reached at the end of the shift, when carrying the loaded fare box, rather than when driving. CONCLUSIONS: Cardiovascular strain during bus driving is much less than during the CCS stress test for drivers. Using CCS methodology, the risk that a sudden cardiovascular incident will cause injury or death of others in the first year after recovery from myocardial infarction is estimated at 1 in 50,000 driver-years. Thus, those satisfying CCS requirements can return to full driving duties promptly, with minimal risk to themselves, passengers, or other road users.

Adult↗
PubMedDate not supplied

Risk profile and health awareness in male offspring of parents with premature coronary heart disease.

BACKGROUND: The offspring of parents who suffer from premature coronary heart disease have a significantly higher risk of early cardiac death than controls. A genetic predisposition is compounded by a commonality of environmental risk factors within families. Increasing awareness, early detection and modification of risk factors are essential components of an effective public health strategy to protect this highly vulnerable population. METHODS: The sons (n = 571) of parents with premature coronary heart disease attended the Toronto Rehabilitation Centre for a risk factor evaluation that included an interview with questionnaire, measurement of body dimensions and blood lipids, and cardiopulmonary exercise testing. A follow-up questionnaire was sent out 2 years after the evaluation. RESULTS: Despite concern about family history, 23% of subjects were smokers and 75% were inactive. Objective data confirmed a substantial prevalence of cardiac risk factors: less than optimal cardiovascular fitness (48%), overweight (34%), total cholesterol > or = 200 mg/dL (46%), high-density lipoprotein cholesterol < or = 35 mg/dL (26%), low-density lipoprotein cholesterol > or = 160 mg/dL (16%), triglycerides > or = 200 mg/dL (27%), and lipoprotein (a) > 30 mg/dL (24%). Although almost all had a family physician whom they had seen an average of 1.8 times in the past year, and 4.7 times in the previous 3 years, screening and risk factor intervention strategies were disappointing. Two-year follow-up data showed a heightened health awareness, with a greater proportion of subjects exercising and attempting to maintain an appropriate body mass. CONCLUSIONS: The male offspring of parents who have suffered a premature coronary event exhibit a substantial prevalence of modifiable risk factors. The family physician can play an essential role in promoting a healthy lifestyle through risk reduction counselling and screening.

Adult↗
PubMedDate not supplied

Paediatric palliative care: a lack of research-based evidence.

Providing the best possible care for the child and family is paramount to health professionals working in paediatric palliative care. However, there is little research which enables practitioners to question their current practice. There are concerns about conducting research on children receiving palliative care at such a sensitive time for the child and his/her family. These concerns must be considered against the growing demand for clear standards and guidelines for practice within health care. According to the Department of Health (DoH) there is no place within the modern healthcare system for the adoption of unproven theories or outdated care (DoH, 1998). While no-one would question the dedication and care being delivered to children and their families by well-trained staff, the lack of research is a cause for concern. A group of students undertaking a degree module in paediatric palliative care identified the lack of literature and research in this area and have undertaken a review of the available literature.

Child↗