Antibiogram data from private hospitals in Hong Kong: 6-year retrospective study.

INTRODUCTION: The surveillance of antibiotic resistance is critical for the establishment of effective control strategies. The antibiotic resistance situations in private hospitals in Hong Kong have not been systematically described. The objective of the study was to analyse antibiogram data from private hospitals and describe the temporal trends of non-susceptibility percentages in this setting. METHODS: This retrospective descriptive study used antibiogram data from all private hospitals in Hong Kong that had been collected annually for 6 years (2014-2019). Data on six targeted bacteria and their corresponding multidrug-resistant organisms were included. RESULTS: The non-susceptibility percentages of isolates remained stable or decreased during the study period: methicillin-resistant Staphylococcus aureus had a stable prevalence of approximately 20%; extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella species had stable prevalences of 20% to 30% and 10% to 20%, respectively; multidrug-resistant Acinetobacter species had prevalences of approximately 2% to 8%, which decreased over time; multidrug-resistant Pseudomonas aeruginosa had prevalences of 0.0% to 0.3%; Streptococcus pneumoniae penicillin and macrolide non-susceptibility percentages were 2% to 9% and 71% to 79%, respectively. These values generally were comparable with findings from public hospitals and Residential Care Homes for the Elderly in Hong Kong. However, the prevalences of carbapenem-resistant Enterobacteriaceae, which are increasing in Hong Kong and other nations, were also increasing in our dataset despite their currently low values (<1% for Escherichia coli and <2% for Klebsiella species). CONCLUSION: The antibiotic resistance landscape among private hospitals in Hong Kong is satisfactory overall; there remains a need for surveillance, antibiotic stewardship, and other infection control measures.

Antibiotic management of acute pharyngitis in primary care.

The Centre for Health Protection of the Department of Health has convened the Advisory Group on Antibiotic Stewardship Programme in Primary Care (the Advisory Group) to formulate guidance notes and strategies for optimising judicious use of antibiotics and enhancing the Antibiotic Stewardship Programme in Primary Care. Acute pharyngitis is one of the most common conditions among out-patients in primary care in Hong Kong. Practical recommendations on the diagnosis and antibiotic treatment of acute streptococcal pharyngitis are made by the Advisory Group based on the best available clinical evidence, local prevalence of pathogens and associated antibiotic susceptibility profiles, and common local practice.

Serum 25-hydroxyvitamin D concentration does not independently predict incident diabetes in older women.

AIMS: To investigate whether 25-hydroxyvitamin D concentration was associated with incident diabetes in a large cohort of older women. METHODS: Data were analysed from women included in the Study of Osteoporotic Fractures, a cohort of community-dwelling women aged ≥65 years at enrolment. Serum 25-hydroxyvitamin D concentration was assessed at the year 6 visit, as were BMI and other factors associated with vitamin D and/or diabetes. Diabetes status was determined at each subsequent visit by self-report and medication use. Only those without prevalent diabetes at the year 6 visit were included in the present analysis (N = 5463, mean age 76.5 years). RESULTS: During a mean ±sd follow-up of 8.6 ± 4.4 years, incident diabetes was reported in 320 participants. The mean BMI was higher in those with a 25-hydroxyvitamin D concentration <20 ng/ml (<50 nmol/l) than in those with concentrations 20-30 or ≥30 ng/ml [50-74 or ≥75 nmol/l (P < 0.0001)]. A higher 25-hydroxyvitamin D concentration was associated with a 13% lower risk of incident diabetes after adjustment for age and clinic site [hazard ratio 0.87, 95% CI 0.76-0.99, per sd increase in 25-hydroxyvitamin D]; however, the addition of BMI to the model attenuated the estimated effect (hazard ratio 0.97, 95% CI 0.86-1.11). Adjustment for additional potential confounders yielded similar results. CONCLUSIONS: Serum 25-hydroxyvitamin D does not independently predict incident diabetes in older women. Although those with higher 25-hydroxyvitamin D concentrations are less likely to develop diabetes, this is mainly explained by their lower BMI.

Emphasizing responder speed or accuracy modulates but does not abolish the distractor-induced quitting effect in visual search.

When a highly salient distractor is present in a search array, it speeds target absent visual search and increases errors during target present visual search, suggesting lowered quitting thresholds (Moher in Psychol Sci 31(1):31-42, 2020). Missing a critical target in the presence of a highly salient distractor can have dire consequences in real-world search tasks where accurate target detection is crucial, such as baggage screening. As such, the current study examined whether emphasizing either accuracy or speed would eliminate the distractor-generated quitting threshold effect (QTE). Three blocks of a target detection search task which included a highly salient distractor on half of all trials were used. In one block, participants received no instructions or feedback regarding performance. In the remaining two blocks, they received instructions and trial-by-trial feedback that either emphasized response speed or response accuracy. Overall, the distractor lowered quitting thresholds, regardless of whether response speed or response accuracy was emphasized in a block of trials. However, the effect of the distractor on target misses was smaller when accuracy was emphasized. It, therefore, appears that while the distractor QTE is not easily eradicated by explicit instructions and feedback, it can be shifted. As such, future research should examine the applicability of these and similar strategies in real-world search scenarios.

The impact of COVID-19 on subthreshold depressive symptoms: a longitudinal study.

AIMS: The coronavirus disease 2019 (COVID-19) pandemic represents an unprecedented threat to mental health. Herein, we assessed the impact of COVID-19 on subthreshold depressive symptoms and identified potential mitigating factors. METHODS: Participants were from Depression Cohort in China (ChiCTR registry number 1900022145). Adults (n = 1722) with subthreshold depressive symptoms were enrolled between March and October 2019 in a 6-month, community-based interventional study that aimed to prevent clinical depression using psychoeducation. A total of 1506 participants completed the study in Shenzhen, China: 726 participants, who completed the study between March 2019 and January 2020 (i.e. before COVID-19), comprised the 'wave 1' group; 780 participants, who were enrolled before COVID-19 and completed the 6-month endpoint assessment during COVID-19, comprised 'wave 2'. Symptoms of depression, anxiety and insomnia were assessed at baseline and endpoint (i.e. 6-month follow-up) using the Patient Health Questionnaire-9 (PHQ-9), Generalised Anxiety Disorder-7 (GAD-7) and Insomnia Severity Index (ISI), respectively. Measures of resilience and regular exercise were assessed at baseline. We compared the mental health outcomes between wave 1 and wave 2 groups. We additionally investigated how mental health outcomes changed across disparate stages of the COVID-19 pandemic in China, i.e. peak (7-13 February), post-peak (14-27 February), remission plateau (28 February-present). RESULTS: COVID-19 increased the risk for three mental outcomes: (1) depression (odds ratio [OR] = 1.30, 95% confidence interval [CI]: 1.04-1.62); (2) anxiety (OR = 1.47, 95% CI: 1.16-1.88) and (3) insomnia (OR = 1.37, 95% CI: 1.07-1.77). The highest proportion of probable depression and anxiety was observed post-peak, with 52.9% and 41.4%, respectively. Greater baseline resilience scores had a protective effect on the three main outcomes (depression: OR = 0.26, 95% CI: 0.19-0.37; anxiety: OR = 1.22, 95% CI: 0.14-0.33 and insomnia: OR = 0.18, 95% CI: 0.11-0.28). Furthermore, regular physical activity mitigated the risk for depression (OR = 0.79, 95% CI: 0.79-0.99). CONCLUSIONS: The COVID-19 pandemic exerted a highly significant and negative impact on symptoms of depression, anxiety and insomnia. Mental health outcomes fluctuated as a function of the duration of the pandemic and were alleviated to some extent with the observed decline in community-based transmission. Augmenting resiliency and regular exercise provide an opportunity to mitigate the risk for mental health symptoms during this severe public health crisis.

Linear photonic radio frequency phase shifter using a differential-group-delay element and an optical phase modulator.

We demonstrate a stable and linear photonic radio frequency (RF) phase shifter based on a differential-group-delay element and the polarization sensitive effect of an optical phase modulator. The phase shift can be tuned continuously over 360 degrees for RF signals over 40GHz with an electrical control voltage from -7.5 to +7.5V.

Cardiac Manifestations of Sarcopenia.

OBJECTIVES: Screening questions for sarcopenia used in the community (SARC-F) may be regarded as indicators of exercise tolerance. DESIGN: Observational study. SETTING: We tested the hypothesis that community-living older people who are screened positive for sarcopenia using the SARC-F tool but without a history of heart failure (HF) have a higher prevalence of cardiac abnormalities compared with those who are SARC-F negative. PARTICIPANTS: Participants were recruited from a territory-wide primary care needs assessment for older people based in community centres, and from non-acute hospitals in the same region as the study centre. MEASUREMENTS: Participants with a total score of >=4 and who did not have any history of HF were invited to attend for further cardiac assessment. Grip strength, walking speed, and the 6-minute walk test and echocardiography were carried out. Patients with frailty and at least Grade II diastolic dysfunction were considered to have heart failure with preserved ejection fraction (HFpEF) if they also had concomitant elevated N-terminal prohormone of B-type natriuretic peptide (NT-proBNP) of at least 300 pg/ml. RESULTS: Diastolic dysfunction (DD) was significantly associated with SARC-F score >=4 and higher circulating NT-proBNP levels. ROC curves evaluating the predictive values of SARC-F, HGS and gait speed for DD showed that a combination of SARC-F and HGS or gait speed provided significant incremental value in predicting DD. CONCLUSIONS: Community living older people with sarcopenia detected using a simple questionnaire have a higher prevalence of DD accompanied by elevated NT proBNP. Addition of hand grip strength or walking speed improve the magnitude of the association. SARC-F may be used as a tool to detect early cardiac dysfunction in the community.

Utility of the FRAIL Questionnaire in Detecting Heart Failure with Preserved Ejection Fraction.

OBJECTIVE: To test the utility of the FRAIL questionnaire as a screening tool for heart failure. DESIGN: Cross sectional study. SETTING: Chinese older people in Hong Kong. PARTICIPANTS: Participants aged 60 years and over were recruited from a territory-wide primary care needs assessment for older people based in community centers as well as two nonacute hospitals. MEASUREMENTS: Questionnaire administered included the five-item FRAIL scale, and information regarding sociodemographic data, smoking and alcohol use, history of cardiovascular disease and diabetes, and heart failure symptoms. Handgrip strength, walking speed and 6 minute walk distance were recorded. Cardiac assessment included electrocardiogram, echocardiography, and blood assay for N-terminal prohormone of B-type natriuretic peptide (NT-proBNP). RESULTS: The prevalence of diastolic dysfunction was high, being 52% in the robust group, increasing to 65% in the pre-frail and 85% in the frail group. This finding is accompanied by a corresponding increase in NT-proBNP from 64.18 pg/ml in the robust group, to 118.57 pg/ml in the pre-frail and 167.98 pg/ml in the frail group. Three of the five components of the FRAIL scale, fatigue, resistance and ambulation, were associated with increased odds ratios of diastolic dysfunction among those aged 75 years and older, while resistance alone was associated with increased odds ratio among those less than 75 years old. CONCLUSION: Frailty is associated with heart failure with preserved ejection fraction (HFpEF), and frailty screening may be used to detect undiagnosed HFpEF. The findings support the proposal that HFpEF be considered a geriatric syndrome.

Osteoprotegerin Lys3Asn polymorphism and the risk of fracture in older women.

CONTEXT: Osteoprotegerin (OPG) is a soluble decoy receptor for receptor activator nuclear factor kappa-beta that blocks osteoclastic bone resorption. OBJECTIVE: We investigated the association between a Lys3Asn polymorphism in the OPG gene and bone mineral density (BMD), and the risk of fracture in 6695 women aged 65 yr and older participating in the Study of Osteoporotic Fractures. DESIGN: BMD was measured using either single-photon absorptiometry (Osteon Osteoanalyzer; Dove Medical Group, Los Angeles, CA) or dual-energy x-ray absorptiometry (Hologic QDR 1000; Hologic, Inc., Bedford, MA). Incident fractures were confirmed by physician adjudication of radiology reports. Genotyping was performed using an immobilized probe-based assay. RESULTS: Women who were homozygous for the minor G (Lys) allele had significantly lower BMD at the intertrochanter, distal radius, lumbar spine, and calcaneus than those with the C (Asn) allele. There were 701 incident hip fractures during 13.6-yr follow-up (91,249 person-years), including 362 femoral neck and 333 intertrochanteric hip fractures. Women with the C/C (Asn-Asn) genotype had a 51% higher risk of femoral neck fracture (95% confidence interval, 1.13-2.02) and 26% higher risk of hip fracture (95% confidence interval, 1.02-1.54) than those with the G/G (Lys-Lys) genotype. These associations were independent of BMD. Intertrochanteric fractures were not associated with the Lys3Asn polymorphism. CONCLUSION: These results require confirmation but suggest a role for the OPG Lys3Asn polymorphism in the genetic susceptibility to hip fractures among older white women.

Efficacy of combination chemotherapy with irinotecan (CPT-11) plus capecitabine in patients with metastatic or advanced colorectal carcinoma--a dual-centre phase II study: the MAC-6.

AIMS: A phase II trial was initiated to evaluate the efficacy and toxicity of combination chemotherapy with irinotecan (CPT-11) plus capecitabine in patients with metastatic colorectal cancer. PATIENTS AND METHODS: Patients received a combination of CPT-11 plus capecitabine. CPT-11 was infused intravenously on day 1 every 2 weeks and oral capecitabine was taken twice daily for 5 days every 7 days. Efficacy and toxicities were assessed. RESULTS: Between 2004 and 2005, 43 patients were enrolled. The overall response rate was 51.35%. With a median follow-up of 13 months, the median time to progression was 10 months (95% confidence interval 7.6-12.3 months); the median survival was 15 months (95% confidence interval 13.9-16.9 months). The most common grade 3 haematological and non-haematological toxicities were neutropenia (5.4%), diarrhoea (8.1%) and hand-foot syndrome (2.7%). CONCLUSIONS: CPT-11 plus capecitabine with a 14 day cycle showed a comparable response with international phase II data with a 3 weekly regimen and was well tolerated as a first-line palliative chemotherapy in patients with metastatic colorectal cancer. The data should be interpreted with caution due to the limited sample size and should be further confirmed by a phase III randomised trial.

Interaction between intruders in vibrated granular beds.

Two neutrally buoyant intruder particles in a granular bed fluidized by vertical, sinusoidal vibration are known to interact with each other over a range of about five intruder diameters. Using molecular dynamics simulations, we investigate in detail the spatial and temporal nature of this interaction. We show that the force of attraction between intruders can be calculated from the local density and kinetic energy using a simple equation of state. Moreover, the interaction can be changed from attractive to repulsive by reducing the coefficient of restitution between the intruders and host particles, one of the key results of this work.

Intruder clustering in three-dimensional granular beds.

We present results of computer simulations for neutrally buoyant intruders in a vertically vibrated three-dimensional granular bed of smaller host particles. Under sinusoidal excitation, pairs of intruders interact over a distance of several intruder diameters; a group of intruders forms a cluster. The strength of the interaction grows as the number of intruders is increased. We show that the tendency to cluster may be manipulated through the use of nonsinusoidal excitation, which allows partial mixing. Finally, we investigate the effects of walls on the clustering of intruders.

Induction chemotherapy with mitomycin, epirubicin, cisplatin, fluorouracil, and leucovorin followed by radiotherapy in the treatment of locoregionally advanced nasopharyngeal carcinoma.

PURPOSE: Survival in advanced nasopharyngeal carcinoma (NPC) is compromised by distant metastasis. Because mitomycin is active against hypoxic and G0 cells, which may help to eradicate micrometastasis, we investigated the effect of mitomycin-containing cisplatin-based induction chemotherapy. PATIENTS AND METHODS: Recruited for this study were American Joint Committee on Cancer (AJCC) 1992 staging system stage IV NPC patients with the following adverse features: obvious intracranial invasion, supraclavicular or bilateral neck lymph node metastasis, large neck node (> 6 cm), or elevated serum lactate dehydrogenase (LDH) level. Patients were given three cycles of chemotherapy before radiotherapy. The chemotherapy comprised a 3-week cycle of mitomycin, epirubicin, and cisplatin on day 1 and fluorouracil and leucovorin on day 8 (MEPFL). RESULTS: From January 1994 to December 1997, 111 patients were recruited. The median follow-up period was 43 months. The actuarial 5-year overall survival rate was 70% (95% confidence interval [CI], 60% to 80%; n = 111). For patients having completed radiotherapy (n = 100), the 5-year locoregional control rate was 70% (95% CI, 55% to 84%) and the distant metastasis-free rate was 81% (95% CI, 73% to 89%). The 5-year distant metastasis-free rate of N3a and N3b disease of AJCC 1997 staging system were 79% (95% CI, 62% to 95%) and 74% (95% CI, 60% to 89%), respectively. By Cox multivariate analysis, high pretreatment serum LDH level (P = .04) and neck nodal enlargement before radiotherapy (P = .001) were adverse prognostic factors of survival. CONCLUSION: The good 5-year survival of N3 disease supports the effectiveness of induction MEPFL in the primary treatment of advanced NPC. Further investigation to incorporate concurrent chemoradiotherapy is warranted.

A prospective study of physical activity and cognitive decline in elderly women: women who walk.

BACKGROUND: Several studies have suggested that physical activity is positively associated with cognitive function in elderly persons. Evidence about this association has been limited by the cross-sectional design of most studies and by the frequent lack of adjustment for potential confounding variables. We determined whether physical activity is associated with cognitive decline in a prospective study of older women. METHODS: We studied 5925 predominantly white community-dwelling women (aged > or =65 years) who were recruited at 4 clinical centers and were without baseline cognitive impairment or physical limitations. We measured cognitive performance using a modified Mini-Mental State Examination at baseline and 6 to 8 years later. Physical activity was measured by self-reported blocks (1 block approximately 160 m) walked per week and by total kilocalories (energy) expended per week in recreation, blocks walked, and stairs climbed. Cognitive decline was defined as a 3-point decline or greater on repeated modified Mini-Mental State Examination. RESULTS: Women with a greater physical activity level at baseline were less likely to experience cognitive decline during the 6 to 8 years of follow-up: cognitive decline occurred in 17%, 18%, 22%, and 24% of those in the highest, third, second, and lowest quartile of blocks walked per week (P< .001 for trend). Almost identical results were obtained by quartile of total kilocalories expended per week. After adjustment for age, educational level, comorbid conditions, smoking status, estrogen use, and functional limitation, women in the highest quartile remained less likely than women in the lowest quartile to develop cognitive decline (for blocks walked: odds ratio, 0.66 [95% confidence interval, 0.54-0.82]; for total kilocalories: odds ratio, 0.74 [95% confidence interval, 0.60-0.90]). CONCLUSIONS: Women with higher levels of baseline physical activity were less likely to develop cognitive decline. This association was not explained by differences in baseline function or health status. This finding supports the hypothesis that physical activity prevents cognitive decline in older community-dwelling women.

Associations of serum osteoprotegerin levels with diabetes, stroke, bone density, fractures, and mortality in elderly women.

Osteoprotegerin (OPG) and its ligand are cytokines that regulate osteoclastogenesis and that may be involved in the regulation of vascular calcification. We examined whether serum OPG levels were associated with stroke, mortality, and cardiovascular risk factors, including diabetes, as well as with bone mineral density and fractures in a sample of 490 participants in a prospective cohort of white women, at least 65 yr of age. We found that OPG levels, assayed blinded from serum obtained at baseline, were about 30% greater in women with diabetes (mean +/- SD, 0.30 +/- 0.17 ng/mL) than in those without diabetes (0.23 +/- 0.10 ng/mL; P = 0.0001). OPG levels were associated with all-cause mortality [age-adjusted odds ratio, 1.4/SD (0.11 ng/mL) increase in serum OPG level; 95% confidence interval, 1.2--1.8] and cardiovascular mortality (odds ratio, 1.4; 95% confidence interval, 1.1--1.8); these effects were not confounded by diabetes. OPG levels were not associated with baseline bone mineral density or with subsequent strokes or fractures. The association of serum OPG levels with diabetes and with cardiovascular mortality raises the possibility that OPG may be a cause of or a marker for vascular calcification.

Nasopharyngeal cancer: study III. A review of 1206 patients treated with combined modalities.

A combination of radiation therapy and chemotherapy was used in an attempt to improve the control of nasopharyngeal cancer (NPC). From 1979 through 1983, 1206 patients with histologically proven NPC were treated with routine radiation along with 5 combinations of drug or drugs in small to maintenance doses. The drugs used were: 1) cyclophosphamide p.o. (CTX), 2) methotrexate p.o. (MTX), 3) CTX + MTX, 4) bleomycin i.v. (BLM), and 5) cisplatin + BLM i.v. (BP). The actuarial survival rates and recurrence rates were chosen as endpoints for comparison to previous studies. The overall survival rate increased from 43.5% in study I, and 56% in study II to 70.6% in the present study. The recurrence rate declined to 13%, but was less impressive. The encouraging results were more obvious in groups of patients with bilateral large cervical lymph nodes, reaching statistical significance (p less than 0.01).

Cell kinetics and radiosensitivity of cervical squamous cell carcinoma.

Flow cytometry analyses of tumors from 12 patients with cervical squamous cell carcinoma under radiotherapy were performed in this preliminary study. Six patients with a high (> 10%) G2/M fraction before treatment showed greater than 50% tumor reduction after initial 2000 cGy radiotherapy. Only two out of six patients with a low (< 10%) G2/M fraction before treatment responded favorably and three of them already had recurrence during the follow-up period of 33-40 months. Hyperploidy (DNA index > 1.1) was observed in 5 patients; all of them responded well to radiotherapy in contrast to three out of seven diploid tumors.

Experience of radiotherapy in lethal midline granuloma with special emphasis on centrofacial T-cell lymphoma: a retrospective analysis covering a 34-year period.

Lethal midline granuloma (LMG) is characterized by progressive ulceration and destruction of the midfacial tissue. It occurs more frequently in Oriental than in Western populations. Because of the progress in clinical pathology and immunohistochemistry, most cases have been proven to be malignant lymphomas, especially of T-cell lineage. We describe 92 cases of lethal midline granuloma or centrofacial malignant lymphoma in the period 1959-1993. All received complete courses of radiotherapy. Twenty of them also received combination chemotherapy. Thirty-six cases had specimens available for immunohistochemical study; 25 (69%) of these had a T-cell phenotype, and 6 (17%) were of B-cell lineage. The dose to the nasal region was in the range of 3000-7500 cGy in 11-58 days, and to the neck 3000-6400 cGy in 11-48 days. The overall survival rate for the LMGs was 59.5% at 5 years and 56.2% at 10 years (Kaplan-Meier). Combined chemotherapy seemed not to improve the overall survival in this study (p = 0.63), but the patient number was too small to make a firm conclusion. Based on the results of this study, we recommend a dose of 4500-5000 cGy to the midfacial region, since a higher dosage did not improve the treatment results (p = 0.88). Irradiation has a definite role in good locoregional control of this disease. The recent clarification of the disease nature and the recognition of the background clinicopathological features should provide valuable information for future patient management and prospective studies.

Inner-city older blacks have high levels of functional disability.

OBJECTIVES: To describe the frequency and severity of functional problems in two groups of noninstitutionalized inner-city blacks aged 70 years and older contrasted with results from appropriate groups of white and black older adults and with the goals of the Healthy People 2000 program. DESIGN: Cross-sectional descriptive study. SETTING: Community-based samples. PARTICIPANTS: A population-based sample of 416 older adults living in a 3.5-square mile catchment area in north St. Louis (NSL), Missouri, and a sample of 197 older residents living in public housing in East St. Louis (ESL), Illinois. MEASUREMENTS: Health status, preventive health activities, health services utilization, and risks for progressive frailty were assessed by self report and observation using well validated, standardized instruments. Whenever possible, comparison data were derived from national datasets, original samples used to validate the measures, and other useful comparison groups. RESULTS: The NSL sample had somewhat better health status and risk for progressive disability than the ESL sample. However, compared with national or regional reference groups using age-gender adjustments, both study groups demonstrated increased levels of dependence in intermediate activities of daily living, restricted activity days, inability to walk one-half mile without assistance, reported poor vision, living alone, and limited income compared with both older whites and blacks, and increased levels of worsening health, inability to perform heavy work around the house, never walking a mile or more, and currently unmarried versus whites with variable decrements versus blacks. Contrasted with other comparison groups, the two samples had increased body fat; consistent decrements in gait speed, timed chair stands, timed one-leg balance, and frequency of preventive exercise; and lower levels of dental care; results relative to physician visits and hospital days were mixed. They also had high levels of measured visual and hearing impairments, unmet needs for home delivered meals, and problems with false teeth. Deficiencies compared with the goals of Healthy People 2000 were large. CONCLUSIONS: The special attributes of inner-city blacks, including poverty and access to and acceptance of remedial programs, will have to be considered if the goals of Healthy People 2000 are to be met in this important and growing segment of older Americans. 44:0000-0000, 1996.

Chromosome aberrations induced in human lymphocytes after partial-body irradiation.

Chromosomal aberrations in peripheral blood lymphocytes obtained from two patients before and after they received one fraction of partial-body irradiation for palliative treatment were analyzed. Blood samples were taken 30 min and 24 h after radiation treatment. The yield of dicentrics obtained from case A 30 min after a partial-body (about 21%) treatment with 8 Gy was 0.066/cell, while the yield obtained 24 h after radiation treatment was 0.071/cell. The fraction of irradiated lymphocytes that reached metaphase at 52 h was 0.08 as evaluated by mixing cultures of in vitro irradiated and unirradiated blood. The yield of dicentrics for blood from case B 30 min after 6 Gy partial-body (about 24%) irradiation was 0.655/cell, while the yield 24 h after irradiation was 0.605/cell. The fraction of irradiated cells was 0.29. Estimation of doses and irradiated fractions for the two cases using the method proposed by Dolphin and the Qdr method is discussed. Although there was no significant difference between the mean yields of dicentrics per cell obtained 30 min and 24 h after radiation treatment, the data obtained at 24 h seemed more useful for the purpose of dose estimation. When a higher dose (8 Gy) was delivered to a smaller percentage of the body, underestimation of the dose was encountered.