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Biomedical subjects

E A Allen

Publications and source records attributed to E A Allen.

At least 37 records · Page 2Linked to original sources
PubMed1991

Tuberculosis in recent Asian immigrants to British Columbia, Canada: 1982-1985.

The prevalence and incidence of active tuberculosis among 21,959 recently arrived (1982-1985) immigrants from 7 selected Asian countries into British Columbia (BC), Canada, were reviewed. Among these newly arrived immigrants, 1173 (5.3%) were judged to have inactive tuberculosis at the immigration examination in their country of origin. In this subgroup, 14 of 932 (1.5%) were found to have active tuberculosis at the initial examination after arrival in Canada. Subsequently, 7 further cases arose in this group of inactive cases giving an average annual incidence rate of 0.33% over the 4-year period of study. Only 3 of these 21 cases had had previous antituberculosis chemotherapy. The remaining 20,786 recent immigrants with normal X-rays at the immigration examination contributed 30 cases during the next 4 years--an average annual incidence rate of 0.08% or 8 times the comparable rate for BC (0.01%). The limitations of the immigration screening process are illustrated and the value of early surveillance of immigrants designated as having inactive tuberculosis is underlined. The apparent failure to exclude active disease prior to the arrival of these immigrants is one factor elevating the incidence of active tuberculosis in the first few years after arrival in the host country. Other factors include the relatively high prevalence of inactive tuberculosis among the immigrants from certain countries and their high rate of early relapse after entry, especially in those not previously treated. Such immigrants should be considered for chemoprophylaxis immediately after entry.

Asia↗
PubMed1990

Molecular characterization of anti-idiotype antibody-resistant variants of a murine B cell lymphoma.

We have previously identified Id- tumor vaiants that emerge after anti-Id mAb therapy of the murine B cell lymphoma 38C13. This report characterizes the molecular basis for these variants. By using a modification of the polymerase chain reaction (PCR), mu and kappa Ig loci were sequenced from nine Id- variants derived directly by anti-Id immunoselection in vivo. Ig kappa loci sequence analysis was also performed from 10 additional variants amplified directly from tumor cells in vitro without immunoselection. We demonstrate that the molecular mechanism underlying tumor cell escape in this model is the spontaneous emergence of variants that have undergone kappa L chain gene "re-rearrangement" before positive selection by the anti-Id antibody. A second round of re-rearrangement was also demonstrated to occur within primary tumor variants. Re-rearrangement of the 38C13 tumor cell Ig kappa locus is strongly biased toward use of variable kappa genes within the conserved V kappa-Ox1 gene family, although their use is not exclusive. With the use of RNA PCR re-rearrangement was documented to occur in vitro at a frequency of approximately 1.0 x 10(-5)/cell. These findings may have important implications for the application of anti-Id antibodies as a therapeutic approach for human lymphomas and for understanding of the Ig gene rearrangement process.

Animals↗
PubMed1989

Tuberculosis in British Columbia among immigrants from five Asian countries, 1982-85.

The influence of immigration from six selected Asian countries--Japan, Korea, Philippines, India, China and Hong Kong--on the incidence of tuberculosis in British Columbia has been examined. During the period 1982-1985 the average annual incidence of bacillary tuberculosis in these immigrants was more than six times as great as the overall British Columbia rate and contributed a quarter of the cases of active bacillary tuberculosis in this province whereas the immigrants from these countries represented only 3.7% of the total population. The clinical patterns of active tuberculosis by birthplace were analysed. A high proportion of cases of lymphadenitis was seen among all immigrants from Asia, particularly those from the Philippines. Both primary and secondary drug resistance was substantially higher than in Canadian-born patients. The frequency of primary drug resistance was higher among patients aged less than 40 years than those aged 40 or more.

British Columbia↗
PubMed1987

Spatial memory and perception in stroke patients: the importance of order effects.

The performance of left and right CVA patients on two tasks, spatial matching and spatial recognition, was compared, using a design which also examined the effects of order of task presentation. All groups performed better on matching than on recognition trials, and the left CVA subjects obtained higher scores than right CVA subjects on both types of trial. A significant lesion X order interaction reflected the particularly poor performance of right CVA subjects who received the more difficult task (recognition) first. The clinical implications are discussed.

Adult↗
PubMed1987

Inner-city survey for tuberculosis: evaluation of diagnostic methods.

A total of 1,271 persons living in a socially and economically depressed, inner-city area of Vancouver, British Columbia, voluntarily attended a tuberculosis case-finding campaign. Chest x-ray, on-the-spot specimen of sputum, and tuberculin skin test were offered at the time of the first attendance. All 3 diagnostic methods were found to be well accepted, with 93% of the participants having an x-ray, over 95% producing a sputum specimen, and almost 95% having a tuberculin test (a quarter of these did not, however, report for reading of the test). Eight cases of bacteriologically confirmed pulmonary tuberculosis were found: 6 suspected on x-ray (the remaining 2 films were abnormal but not diagnostic of tuberculosis), and 6 being positive on smear and/or culture of the initial on-the-spot sputum specimen. Examination of a second specimen of sputum diagnosed all of the 8 active cases identified by the survey. These results suggest that, in this particular setting, a chest radiogram taken by a transportable chest x-ray apparatus or examination of 2 sputum specimens might be equally successful at detecting all cases of active pulmonary tuberculosis within the time required for sputum culture. Examination of the sputum smear immediately identifies all the more infectious cases of pulmonary tuberculosis. The prevalence rate of 629 per 100,000 among those presenting themselves to this campaign illustrates the high-yield which might be achieved by active case-finding projects in known high-incidence segments of a generally low-incidence population.

Adult↗
PubMed1987

Significance of the tuberculin test in the elderly.

Nine hundred thirty-three persons over 65 years of age, residing in long-term or extended-care facilities in Vancouver, Canada, had tuberculin tests. In addition to PPD-tuberculin, 5 TU and 250 TU, we used PPD-Battey, Candida albicans, mumps, and Trichophyton antigens. Twenty-five percent reacted to 5 TU of tuberculin with reactions of 10 mm or more. There was a progressive, substantial loss of reactivity with advancing age. Reactions to PPD-Battey greater than to PPD-T 5 TU were infrequent, suggesting that atypical mycobacterial infections were uncommon and that positive reactions to PPD-T, 250 TU, were predominantly caused by infections with Mycobacterium tuberculosis. Based on the results of both 5 TU and 250 TU, the prevalence of tuberculous infection exceeded 60 percent. Waning of tuberculin sensitivity appears to be an integral part of the aging process. Testing with nonmycobacterial antigens used in this study shed no further light on the problem of anergy in the elderly, as the number of reactors was smaller than that obtained with PPD-tuberculin.

Aged↗
PubMed1985

Isolation and geographic distribution of Mycobacterium other than M. tuberculosis in British Columbia, 1972-81.

It has been suggested that the incidence of infection with mycobacteria other than typical tubercle (MOTT) bacilli is increasing. Laboratory and epidemiologic information relating to MOTT infection in British Columbia between 1972 and 1981 was analysed. Patient records for 1960-81 were also analysed. Of the 313 661 laboratory specimens 13 474 yielded Mycobacterium tuberculosis isolates and 3172, MOTT isolates. Over the 10 years the number of M. tuberculosis isolates declined, whereas the absolute and relative numbers of MOTT isolates increased. Members of the highly drug-resistant MAIS complex (M. avium-intracellulare, M. scrofulaceum and M. simiae) accounted for 73.3% of the 1778 potentially pathogenic MOTT isolates. MAIS isolation rates varied geographically. Analysis of patient records revealed 217 MOTT infections, of which 152 (70%) were due to MAIS organisms. Further studies are needed to determine the source of MAIS organisms in order that the infection and the disease may be more clearly understood.

British Columbia↗
PubMed1985

Tuberculosis in female nurses in British Columbia: implications for control programs.

All 57 cases of active tuberculosis in women in nursing and related assisting occupations (henceforth called nurses) notified in British Columbia between 1969 and 1979 were reviewed. This represented a mean annual incidence of active tuberculosis of 2.6/10 000, similar to that in other women, adjusted for age and birthplace. The rate varied according to birthplace: among nurses born in Canada the rate was 2.0, almost twice that of other women born in Canada, and among those born in Asia it was 24.8, less than half that of other women born in Asia. The nurses born in Canada who had received BCG (bacille Calmette-Guérin) during their training were least likely to contract tuberculosis, the incidence rate being comparable to that among other women. Those whose results of tuberculin testing were negative but who were not vaccinated were twice as likely to contract tuberculosis, whereas those whose results were positive at the start of training were four times as likely to contract tuberculosis. The feasibility and implications of a tuberculosis screening and surveillance program are discussed.

Adolescent↗
PubMed1985

Microscopic evaluation of sputum specimens submitted for Mycobacterium tuberculosis culture.

Using microscopic screening criteria employed in the study of sputum in acute bacterial pneumonia, the authors evaluated 644 sputum samples from 347 patients submitted for mycobacterial bacterial culture. After microscopic examination, these specimens were processed using standard mycobacterial laboratory technics. Salivary specimens accounted for 67.1% of the samples evaluated, and yielded 13 of the total 42 Mycobacterium tuberculosis isolates, as well as 4 of the 21 smear-positive culture-positive specimens. Although specimens from the lower respiratory tract are preferred, specimens of a salivary nature should not be discarded by the Mycobacteriology Laboratory.

Cells, Cultured↗
PubMedDate not supplied

Behavioral auditory function after transection of crossed olivo-cochlear bundle in the cat. V. Pure-tone intensity discrimination.

This report describes the cat's ability to discriminate pure-tone intensity differences after transection of the crossed olivo-cochlear bundle at the floor of the fourth ventricle. Cats were trained by behavioral (avoidance) conditioning to detect intensity difference above 75 dB re 0.0002 dyne/cm2 of 10 000 Hz tones, using the repetitive method. Postoperative comparison of data from 5 experimental animals and 5 sham-operated control animals showed minimal differences which reflects merely functional biological variance. Neurohistological examination confirmed the accuracy of the lesion placement.

Acoustic Stimulation↗