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Biomedical subjects

J S Jackson

Publications and source records attributed to J S Jackson.

At least 19 recordsLinked to original sources
PubMed2000

Effect of time interval between breast-conserving surgery and radiation therapy on ipsilateral breast recurrence.

PURPOSE: To examine the effect of the time interval (interval) between breast-conserving surgery (BCS) and the start of radiation therapy (RT) on the subsequent risk of ipsilateral breast cancer recurrence (IBR). METHODS AND MATERIALS: We reviewed interval and a number of prognostic and treatment factors among 1,962 women treated with BCS and RT for invasive breast cancer diagnosed between January 1, 1989 and December 31, 1993 in British Columbia, Canada. Subjects were female, less than 90 years old at diagnosis, not treated with chemotherapy, not stage T4 or M1, and had survived more than 30 days from diagnosis. The cumulative incidence of IBR was estimated in four interval groups: 0-5, 6-8, 9-12, and 13+ weeks. Only 23 women had an interval of greater than 20 weeks between BCS and start of RT. To assess whether an imbalance of prognostic and treatment factors could be obscuring real differences between the interval groups, Cox proportional hazards regression analyses were conducted. RESULTS: Median follow-up was 71 months. The crude incidence of IBR for the entire sample was 3.9%. The cumulative incidence of IBR in the 6-8, 9-12, and 13+ week groups was not statistically significantly different from the cumulative incidence of IBR in the 0-5 week group. Multivariate analyses demonstrated that patients not using tamoxifen p = 0.027) and those with grade 3 histology (p = 0.003) were more likely to recur in the breast. Interval between BCS and RT was not a statistically significant predictor of breast recurrence when entered into a model incorporating tamoxifen use and tumor grade (0-5 vs. 6-8 weeks, p = 0.872; 0-5 vs. 9-12 weeks, p = 0.665; 0-5 vs. 13+ weeks, p = 0.573). CONCLUSIONS: We found no univariate or multivariate difference in ipsilateral breast cancer recurrence between intervals of 0 to 20 weeks from breast conserving surgery to start of radiation therapy, in a population-based, low risk group of women not receiving adjuvant chemotherapy, after controlling for other factors important in predicting ipsilateral breast cancer recurrence.

Adult↗
PubMed1999

Inhaled uranium ore dust and lung cancer risk in rats.

Using a nose-only inhalation system, male Sprague-Dawley rats were exposed 4.2 h d(-1), 5 days per week for 65 weeks to one of two concentrations of natural uranium ore dust aerosol (44% U, 50 mg m(-3) and 19 mg m(-3)) without significant radon content. After inhalation exposure ceased, the rats were allowed to live for their natural lifetime. Lung uranium burdens, measured at the time of death of each animal, declined exponentially after dust inhalation ceased, and the rate of decline was independent of the initial lung burden. Lymph node specific burdens ranged from 1 to 60 fold greater than the specific lung burden in the same animal. No lymph node tumors were observed. The frequency of primary malignant lung tumors was 0.016, 0.175 and 0.328 and primary non-malignant lung tumors 0.016, 0.135 and 0.131 in the control, low and high aerosol exposed groups, respectively. There was no difference in tumor latency between the groups. Absorbed dose to the lung was calculated for each animal in the study. The average doses for all the animals exposed to the low and high dust aerosol concentrations were 0.87 Gy and 1.64 Gy respectively, resulting in an average risk of malignant lung tumors of about 0.20 tumors per animal per Gy in both groups. The frequency of primary lung tumors was also calculated as a function of dose increment for both exposed groups individually and combined. The data indicate that, in spite of the above result, lung tumor frequency was not directly proportional to dose. However, when malignant lung tumor frequency was calculated as a function of dose rate (as measured by the lung burden at the end of dust inhalation) a direct linear relationship was seen (p < 0.01) suggesting dose rate may be a more important determinant of lung cancer risk than dose. Conversely, non-malignant lung tumors were significantly correlated with low lung burdens (p = 0.01). We conclude that chronic inhalation of natural uranium ore dust alone in rats creates a risk of primary malignant and non-malignant lung tumor formation and that malignant tumor risk was not directly proportional to dose, but was directly proportional to dose rate.

Adenocarcinoma↗
PubMed1999

The adaptive response modifies latency for radiation-induced myeloid leukemia in CBA/H mice.

We have investigated the effect of the adaptive response on acute myeloid leukemia (AML) induced in CBA/Harwell mice by a chronic radiation exposure. Groups of mice irradiated with a total dose of 1. 0 Gy at two different chronic dose rates (0.5, 0.004 Gy/h) had similar frequencies of AML. Compared to control animals that did not develop AML, irradiation at either of these dose rates did not change the longevity of the mice that did not die of leukemia. The survival rates of irradiated mice that did develop leukemia in the two groups were not different from each other, indicating that the dose rates produced similar responses and therefore were both chronic exposures. We then tested the ability of a chronic 10-cGy (0. 5 Gy/h) exposure to ionizing radiation, mild hyperthermia (40.5 degrees C whole-body, 60 min) or treatment with interleukin-1 (1500 U i.p.) to induce an adaptive response and modify the frequency or latency of AML which resulted from a subsequent (24 h later) 1.0-Gy (0.5 Gy/h) chronic radiation exposure. The frequency of radiation-induced leukemia was not changed in mice given any of the three adapting treatments 24 h prior to the chronic 1.0-Gy dose that induced leukemia. However, the latent period for development of AML was significantly increased by both the prior low radiation dose and mild hyperthermia treatment. Injection of interleukin-1, in contrast, may have reduced the latent period. Similar to the single 1.0-Gy chronic exposure alone, none of the adapting treatments prior to that exposure influenced the survival of animals that did not develop AML. These results indicate that an earlier exposure to a small adapting dose of radiation or to a mild heat stress can influence secondary steps in radiation-induced carcinogenesis.

Acute Disease↗
PubMed1999

Psychiatric diagnosis of African Americans: diagnostic divergence in clinician-structured and semistructured interviewing conditions.

This study is a primary data collection that varied patient race and diagnosis and used two diagnostic interviewing conditions: one clinician-structured (phase one) and the other a semi-structured diagnostic instrument (phase two). Four basic research questions are addressed: What is the relationship between race and the hospital diagnosis? How is race related to diagnosis in both research interviewing conditions? Why does diagnostic concordance between the hospital diagnosis and the research diagnosis vary by research interviewing condition? Is diagnostic concordance between the hospital and research diagnosis influenced by patient race? A total of 291 patients completed an interview during phase one, while 665 patients completed an interview during phase two. Blacks were more likely to receive a hospital diagnosis of schizophrenia and less likely to be diagnosed with mood disorder. Patient race was similarly related to the research diagnoses produced in the clinician-structured research condition (phase one). Although less pronounced, a higher percentage of African Americans than whites received a diagnosis of schizophrenia using the semi-structured DSM-III-R Symptom Checklist (phase two). The black-white distribution for mood disorders showed that whites were more likely than blacks to be diagnosed with mood disorder.

Adult↗
PubMed1998

Prediction of axillary lymph node involvement of women with invasive breast carcinoma: a multivariate analysis.

BACKGROUND: The increasing use of systemic therapy for women with lymph node negative breast carcinoma and earlier stage of disease at mammographic detection raises questions regarding the need for routine axillary lymph node dissection. Predictive modeling for lymph node involvement may be one way to reduce the need for axillary lymph node dissection and its morbidity. METHODS: A multivariate analysis of 12 factors predictive of axillary lymph node involvement was conducted in a population-based cohort of 4312 women with invasive breast carcinoma diagnosed between January 1, 1993 and December 31, 1996. RESULTS: Clinical palpability, lymphatic or vascular invasion, lesion size, margin status, histology, and patient age were independent predictors of axillary lymph node involvement. The model correctly identified lymph node status in 76.6% of cases. Model accuracy and fit were equally high when applied to randomly selected halves of the study subjects. Approximately 32.0% of the patients in the study sample (1363/4312) were identified as having an extremely high (91%; n = 1102) or low (10%; n = 261) risk of lymph node involvement. In a second analysis, a clinically useable, three-variable model identified a very low risk group of patients (n = 147) with a 4.8% risk of lymph node metastasis and a high risk group of patients (n = 1008) with a 74.2% risk of lymph node metastasis. Greater than 90% of subjects in the high risk group received adjuvant systemic therapy even if they were lymph node negative pathologically. CONCLUSIONS: A clinically useable, three-variable model employing tumor and lymph node palpability, size, and lymphatic or vascular invasion can identify women with invasive breast carcinoma in whom axillary lymph node dissection is very unlikely to alter recommendations regarding adjuvant systemic therapy.

Adult↗
PubMed1997

Aggressiveness of colon carcinoma in blacks and whites. National Cancer Institute Black/White Cancer Survival Study Group.

Black patients with colon cancer in the Black/White Cancer Survival Study were found to have a poorer survival than white patients. More advanced-stage disease at diagnosis was the primary determinant, accounting for 60% of the excess mortality. After adjusting for stage, factors such as poverty, other socioeconomic conditions, and treatment did not further explain the remaining survival deficit. This study examined the aggressiveness of colon tumors in blacks and whites to explore its role in the racial survival differences. Tumor characteristics of 703 cases of newly diagnosed invasive colon adenocarcinoma were centrally evaluated by a gastrointestinal pathologist, blinded in regard to the age, race, and sex of the patients. Blacks were less likely to have poorly differentiated (grade 3) tumors [odds ratio (OR), 0.44; 95% confidence interval, 0.22-0.88] and lymphoid reaction (OR, 0.49; 95% confidence interval, 0.26-0.90) when compared with whites. These black/white (B/W) differences remained statistically significant after adjusting for age, sex, metropolitan area, summary stage, socioeconomic status, body mass index, and health care access and utilization. In addition, blacks were less likely to have high-grade (grade 3) nuclear atypia, mitotic activity, and tubule formation, although these ORs did not reach a statistical significance level of 0.05. Similar B/W differences were observed for patients with advanced disease but not with early stage. Comparison by anatomical subsite showed that blacks had statistically significantly better differentiated tumors for cancers of the proximal and transverse colon but not for the distal. No racial differences were found for blood vessel and lymphatic invasion, necrosis, fibrosis, and mucinous type of histology. The findings, therefore, are the opposite of those hypothesized. After adjusting for stage, more aggressive tumor characteristics do not explain the adverse survival differential in blacks. This suggests that there may be racial differences in environmental exposure, and that the intensity and mode of delivery of carcinogen insult as well as host susceptibility may differ by race and anatomical subsite. Future studies should explore the B/W differences in tumor biology using molecular markers that precede the conventional histological parameters evaluated here.

Adult↗
PubMed1996

Recruitment and retention of African American patients for clinical research: an exploration of response rates in an urban psychiatric hospital.

The issues related to recruiting African American psychiatric inpatients are discussed in the context of a study on the influence of ethnicity on psychiatric diagnosis. Ethnically diverse psychiatric residents interviewed 960 Black and White inpatients in 2 urban psychiatric hospitals. Despite the obstacles cited in the literature about recruiting and retaining African Americans into research, 78% of this sample were African American. In addition, interview completion and refusal rates did not differ by patient ethnicity. Results suggest that matching interviewer and patient ethnicity did not influence African Americans' likelihood of participating in or of refusing an interview. This article summarizes a number of guidelines that others may find useful in conducting clinical research with African Americans, ranging from the formation of academic-public liaisons to interviewer training.

Adult↗
PubMed1996

Perceived race-based discrimination, employment status, and job stress in a national sample of black women: implications for health outcomes.

Previous research has not systematically examined the relationship of perceived race-based discriminations to labor force participation or job related stresses-problems experienced by Black women. The present study investigated the relative contributions of perceived race-based discriminations and sociodemographic characteristics to employment status and job stress in a national probability sample (the National Survey of Black Americans; J. S. Jackson, 1991) of Black women in the United States. Logit and polychotomous logistic regression analyses revealed that Black women's current employment status was best explained by sociodemographic measures. In contrast, the combination of perceived discrimination and sociodemographics differentially affects patterns of employment status and perceived job stress in the work environment of Black women. Implications of these findings for the health of African American women are discussed.

Adult↗
PubMed1996

Vital status in the National Panel Survey of Black Americans: a test of the National Death Index among African Americans.

To test the specificity of the National Death Index (NDI), information was submitted on 157 randomly selected respondents from the National Panel Survey of Black Americans (NPSBA) who were known to be living as of 1992. Information also was submitted for 153 known deceased respondents from the panel survey to test the sensitivity of the NDI. The NDI was very sensitive; however, specificity was somewhat less impressive. Although we found the NDI/NPSBA match to be highly accurate, there was a nontrivial number of false positives.

Black or African American↗
PubMed1995

Relative biological effectiveness of tritium for induction of myeloid leukemia in CBA/H mice.

To help resolve uncertainties as to the most appropriate weighting factor for tritium beta rays, a large experiment was carried out to measure the relative biological effectiveness (RBE) of tritiated water compared to X rays for the induction of myeloid leukemia in male mice of the CBA/H strain. The study was designed to estimate the lifetime incidence of myeloid leukemia in seven groups of about 750 mice each; radiation exposures were approximately 0, 1, 2 and 3 Gy both for tritiated water and for X rays. The lifetime incidence of leukemia in these mice increased from 0.13% in the control group to 6-8% in groups exposed to higher radiation doses. The results were fitted to various equations relating leukemia incidence to radiation dose, using both the raw data and data corrected for cumulative mouse-days at risk. The calculated RBE values for tritium beta rays compared to X rays ranged from 1.0 +/- 0.5 to 1.3 +/- 0.3. A best estimate of the RBE for this experiment was about 1.2 +/- 0.3. A wR value of 1 would thus appear to be more appropriate than a wR of 2 for tritium beta rays.

Animals↗
PubMed1991

AIDS survey methodology with black Americans.

Unique substantive and methodological issues are involved in conducting survey research on sexual and HIV risk related behaviors among Americans of African descent. Problem conceptualization, sampling, design of instruments, mode of data collection, interviewer/respondent characteristics, community resistance, and data analysis and interpretation are discussed. The lack of survey research on sensitive health issues is noted. Possible methods for addressing these issues are drawn from the experiences of the authors in conducting national research on the general and at risk Black community populations. It is concluded that attention to these issues can substantially improve the quality of research on AIDS related behaviors on Black communities. Finally, it is suggested that behavioral theories and sophisticated methodological and analytic approaches, sensitive to the special cultural dimensions of racial/ethnic life in the United States, would contribute substantially to the scientific armamentarium needed to successfully meet the challenge of the AIDS epidemic.

Acquired Immunodeficiency Syndrome↗
PubMed1989

The influence of racial factors on psychiatric diagnosis: a review and suggestions for research.

Research on race and diagnosis initially focused on black-white differences in depression and schizophrenia. Statistics showing a higher treated prevalence of schizophrenia and a lower prevalence of depression for blacks seemed to support the claim that blacks did not suffer from depression. Others argued, however, that clinicians were misdiagnosing depression in blacks. This article reviews empirical studies of racial differences in individual symptoms and summarizes the evidence on misdiagnosis. It argues that more attention must be paid to resolving two contradictory assumptions made by researchers working in the area of race and diagnostic inference: (1) blacks and whites exhibit symptomatology similarly but diagnosticians mistakenly assume that they are different; (2) blacks and whites display psychopathology in different ways but diagnosticians are unaware of or insensitive to such cultural differences. The article concludes with suggested research directions and a discussion of critical research issues.

Black or African American↗
PubMed1989

Age differences in productive activities.

Age differences in productive contributions through both paid and unpaid work are examined in commensurate terms. Data are from a nationwide household survey of 3,617 adults age 25 and older conducted in 1986. Older Americans participate in many unpaid productive activities at levels that are comparable to those reached by middle-aged and younger Americans; these activities include volunteer work in organizations, informal help to others, maintenance and repair of their home and possessions, and housework. Relatively few older Americans spend any time participating in paid work and unpaid rearing of children. Largely because of the cessation of paid work and child care, older Americans spend less time overall in productive activities. Women and men spend about equal time in productive activities, but women spend more of it in unpaid work and less of it in paid work. The difficulties with using paid work as the major indicator for describing productivity across the life span are discussed.

Activities of Daily Living↗
PubMed1989

Hypertension in blacks: psychosocial and biological perspectives.

The extraordinarily high rate of hypertension in blacks remains a significant public health issue in most industrialized societies. Research has focused on the investigation of racial differences in biological, nutritional, behavioural and psychological, and social factors in an effort to identify the causes of this high morbidity rate. Thus far, research suggests important racial differences in renal functioning, particularly in sodium metabolism and plasma renin activity, as well as potassium intake and sodium:potassium ratio. Behavioral factors such as anger-coping style and John Henryism, and social factors such as socioeconomic status, socioecological stress, social support, urban-rural residence, and family interaction patterns have also been identified as potential contributors. Finally, emerging research paradigms such as laboratory stress reactivity and 24-h ambulatory monitoring of blood pressure may provide promising leads about the interaction between these effects and hypertension in black populations.

Black or African American↗
PubMed1987

The health, physical functioning, and informal supports of the black elderly.

Among the elderly population, blacks are increasing more rapidly--and perhaps differently--than whites. Cross-sectional data from two unique surveys describe their heterogeneity in health, physical functioning, and social networks at "younger," middle, and "older" ages. The relation between age and these factors may be nonlinear; indeed, evidence supports the contention of a racial "crossover" at advanced ages. Life experiences--ecological, social, economic, and familial--of successive cohorts are likely to pose different problems for elderly blacks in the future. Further research into these differences should inform public policy.

Activities of Daily Living↗