Mammographic image restoration using maximum entropy deconvolution.

An image restoration approach based on a Bayesian maximum entropy method (MEM) has been applied to a radiological image deconvolution problem, that of reduction of geometric blurring in magnification mammography. The aim of the work is to demonstrate an improvement in image spatial resolution in realistic noisy radiological images with no associated penalty in terms of reduction in the signal-to-noise ratio perceived by the observer. Images of the TORMAM mammographic image quality phantom were recorded using the standard magnification settings of 1.8 magnification/fine focus and also at 1.8 magnification/broad focus and 3.0 magnification/fine focus; the latter two arrangements would normally give rise to unacceptable geometric blurring. Measured point-spread functions were used in conjunction with the MEM image processing to de-blur these images. The results are presented as comparative images of phantom test features and as observer scores for the raw and processed images. Visualization of high resolution features and the total image scores for the test phantom were improved by the application of the MEM processing. It is argued that this successful demonstration of image de-blurring in noisy radiological images offers the possibility of weakening the link between focal spot size and geometric blurring in radiology, thus opening up new approaches to system optimization.

Cervical cancer screening among Chinese immigrants in Seattle, Washington.

INTRODUCTION: Chinese American women have high rates of invasive cervical cancer, compared to the general population. However, little is known about the Pap testing behavior of ethnic Chinese immigrants. METHODS: We conducted a community-based survey of Chinese immigrants living in Seattle, Washington, during 1999. Two indicators of cervical cancer screening participation were examined: at least one previous Pap smear and Pap testing in the last 2 years. RESULTS: The overall estimated response rate was 64%, and the cooperation rate was 72%. Our study sample for this analysis included 647 women. Nearly one quarter (24%) of the respondents had never had a Pap test, and only 60% had been screened recently. Factors independently associated with cervical cancer screening use included marital status, housing type, and age at immigration. CONCLUSION: Our findings confirm low levels of cervical cancer screening among Chinese immigrants to North America. Culturally and linguistically appropriate Pap testing intervention programs for less acculturated Chinese women should be developed, implemented, and evaluated.

Hepatitis B knowledge among Vietnamese immigrants: implications for prevention of hepatocellular carcinoma.

BACKGROUND: Vietnamese have higher liver cancer rates than any other racial/ethnic group in the United States. Approximately 80% of liver cancers are etiologically associated with hepatitis B virus (HBV) infection, which is endemic in Southeast Asia. METHODS: A telephone survey of randomly selected Vietnamese households (n = 75) was conducted during 1998 to examine HBV knowledge among Seattle's Vietnamese community. The questionnaire included items related to the transmission of HBV, the possible sequelae of infection, and disease prevention. RESULTS: The response rate was 70% among reachable and eligible households. Prior to being provided with a description of the disease, two thirds of our respondents had heard of HBV infection. Less than 60% knew that asymptomatic individuals can transmit the disease to others. Most thought that HBV infection can cause liver cancer (63%) and death (80%). However, only a minority knew that infection can be lifelong (38%) and incurable (22%). Finally, 28% had never heard of the HBV vaccine. There were significant associations between knowledge and educational level as well as home ownership. CONCLUSIONS: The findings suggest that Vietnamese immigrants have low levels of knowledge about HBV infection, and indicate a need for targeted educational interventions aimed at reducing HBV-related liver cancer mortality.

Breast cancer screening among Cambodian American women.

Our aim was to describe and identify factors associated with breast cancer screening among Cambodian American women. We conducted a cross-sectional survey of 1,365 households using bilingual and bicultural interviewers. We found that low proportions of Cambodian American women were up to date on their clinical breast examinations (CBE; 42%) and mammograms (40%). More than 80% of women with female physicians have had at least one prior screening, and 52% have had the tests recently. Women with male Asian American physicians were less likely to have had screening as compared to women with female non-Asian physicians: ever had CBE (odds ratio [OR], 0.26); recent CBE (OR, 0.39); ever had mammogram (OR, 0.36); and recent mammogram (OR, 0.22). Breast cancer screening among Cambodian American women lags behind the general U.S. population. Tailored promotion efforts should address barriers and promote cancer screening by physicians, staff, and organizations serving this population.

Pap Testing Stages of Adoption among Cambodian Immigrants.

PURPOSE: We examined levels of Pap testing and factors associated with screening participation among Cambodian refugees. METHODS: A community-based, in-person survey was conducted in Seattle during late 1997 and early 1998. Interviews were completed by 413 women; the estimated response rate was 73%. We classified respondents into four Pap testing stages of adoption: precontemplation/contemplation (never screened), relapse (ever screened but did not plan to be screened in the future), action (ever screened and planned to be screened in the future), and maintenance (recently screened and planned to be screened in the future). Bivariate and multivariate techniques were used to examine various factors. FINDINGS: About one-quarter (24%) of the respondents has never been screened, and a further 22% had been screened but did not plan to obtain Pap tests in the future. Fifteen percent were in the action stage and 39% were in the maintenance stage. The following factors were independently associated with cervical cancer screening stages: previous physician recommendation; younger age; beliefs about Pap testing for post-menopausal women, screening for sexually inactive women, and regular checkups; provider ethnicity; prenatal care in the US; and problems finding interpreters. CONCLUSIONS: Our findings confirm low Pap testing rates among Cambodian immigrants, and suggest that targeted interventions should be multifaceted.

Bridging cultures through the development of a cervical cancer screening video for Cambodian women in the United States.

BACKGROUND: Southeast Asian women have higher invasive cervical cancer rates than any other U.S. racial/ethnic population subgroup, and their levels of Pap testing do not even approach the year 2000 goals. Video is a particularly useful medium for cancer education in Cambodian refugee communities because of low literacy levels and high rates of VCR ownership. METHODS: The authors produced a motivational Pap-testing video for Cambodian American women. The 18-minute Khmer-language video is entitled "The Preservation of Traditions." Content, with respect to cervical cancer screening barriers and facilitators, was guided by intensive qualitative data collection. Barriers addressed were: beliefs that traditional postpartum practices protect against cervical disease, Cambodians do not get cervical cancer, and screening is unnecessary; fear of cancer as well as surgery; lack of understanding about preventive concepts and familiarity with the Pap test; concerns about embarrassment and pain; and problems with transportation and child care. Facilitators included the availability of female physicians and interpreters. A community coalition of Cambodian women and two community advisors participated in all aspects of the video development and production. Video techniques frequently used in American productions were adapted to the target audience. For example, cultural context was provided, use of biomedical terminology minimized, role modeling emphasized, and testimonial accounts avoided. CONCLUSION: The processes used to translate empirical evidence into meaningful educational messages, and to adapt American behavioral change techniques to Cambodian cultural norms, are generalizable to other less acculturated immigrant groups and cancer education topics.

Perfluorochemical liquid-enhanced adenoviral vector distribution and expression in lungs of spontaneously breathing rodents.

Perfluorochemical (PFC) liquids have been shown to improve gas exchange and lung compliance in models of lung injury. We reasoned they may also be useful as a vehicle for gene transfer by improving transgene distribution throughout the lung as well as increasing total transgene expression. We have developed a model for PFC liquid use in spontaneously breathing rodents that obviates the need for intubation and ventilation. Intratracheal instillation of the adenoviral vector Adlac-Z resulted in patchy distribution of beta-galactosidase (beta-gal) activity as demonstrated using X-gal histochemistry. In contrast, in rats instilled with Adlac-Z followed by instillation of PFC liquid, more uniformly distributed and increased beta-gal activity was observed. Activity in distal airway and alveolar epithelium was particularly increased. Quantitative measure of beta-gal activity in lung homogenates demonstrated a 3- to 6-fold increase in total activity in lungs of rats receiving Adlac-Z and PFC liquid compared to animals receiving Adlac-Z alone. These studies show that PFC liquids can enhance both the distribution and the total amount of transgene expressed following adenoviral-mediated vector transfer to lungs during spontaneous breathing. Use of PFC liquids may increase the efficacy of gene transfer strategies for treatment of cystic fibrosis and other lung diseases.

Cervical cancer screening among Cambodian-American women.

Southeast Asian women have higher invasive cervical cancer incidence rates and lower Pap testing frequencies than most other racial/ethnic groups in the United States. However, there is little information about the cervical cancer screening behavior of Cambodian-American women. Cambodian residents of Seattle were surveyed in person during late 1997 and early 1998. The PRECEDE model was used to guide the development of items that assessed predisposing, reinforcing, and enabling factors associated with cervical cancer screening participation. The estimated overall survey response was 72%. Four hundred thirteen women completed our questionnaire. Approximately one-quarter (24%) of the respondents had never had a Pap test, and over one-half (53%) had not been screened recently. The following variables were positively associated with a history of at least one Pap smear: younger age, greater number of years since immigration, belief about Pap testing for postmenopausal women, prenatal care in the United States, and physician recommendation. Women who believed in karma were less likely to have ever been screened for cervical cancer than those who did not. Six variables independently predicted recent screening: age; beliefs about regular checkups, cervical cancer screening for sexually inactive women, and the prolongation of life; having a female doctor; and a previous physician recommendation for Pap testing. The study findings indicate that culturally specific approaches might be effective in modifying the cervical cancer screening behavior of immigrant women. Programs targeting Cambodian-Americans are likely to be more effective if they are multifaceted and simultaneously address predisposing, reinforcing, and enabling factors.

Heterologously expressed inner lipoyl domain of dihydrolipoyl acetyltransferase inhibits ATP-dependent inactivation of pyruvate dehydrogenase complex. Identification of important amino acid residues.

The activity of the pyruvate dehydrogenase multienzyme complex (PDC), which catalyses the oxidation of pyruvate to acetyl-CoA within the mitochondrion, is diminished in animal models of diabetes. Studies with purified PDC components have suggested that the kinases responsible for inactivating the decarboxylase catalytic subunits of the complex are most efficient in their regulatory role when they are bound to dihydrolipoyl acetyltransferase (E2) subunits, which form the structural core of the complex. We report that the addition of an exogenous E2 subdomain (inner lipoyl domain) to an intact PDC inhibits ATP-dependent inactivation of the complex. By combining molecular modelling, site-directed mutagenesis and biophysical characterizations, we have also identified two amino acid residues in this subdomain (Ile229 and Phe231) that largely determine the magnitude of this effect.

Adverse events associated with exchange transfusion in healthy and ill newborns.

OBJECTIVE: To determine the incidence of adverse events attributable to exchange transfusion during the past 15 years and compare the incidence of severe complications between healthy and ill infants. DESIGN: Medical records for the past 15 years from two teaching hospitals with neonatal intensive care units were reviewed. Those newborns who underwent exchange transfusions were classified as healthy or ill. Adverse events were analyzed to determine whether they were attributable to the procedure. RESULTS: Of the 106 patients who underwent exchange transfusion, 81 were healthy and had no medical problems other than jaundice. The remaining 25 patients were classified as ill and had medical problems ranging from mild to severe. At least 2 (2%) of the 106 patients died of complications probably attributable to exchange transfusion. None of the 81 healthy infants died, but 1 had severe necrotizing enterocolitis requiring surgery. Of the 25 ill infants, at least 3 (12%) experienced severe complications (including 2 deaths) probably attributable to exchange transfusion. Serious complications from the most common adverse events, hypocalcemia and thrombocytopenia, were limited to the group of infants already ill with other medical problems. CONCLUSIONS: Because of the significantly greater rate of severe complications in ill infants, exchange transfusion should be delayed until the risk of bilirubin encephalopathy is as high as the risks of severe complications from the procedure itself (12%). These results do not support recommendations to use lower exchange levels in ill infants compared with healthy infants.

Reduction in lung injury after combined surfactant and high-frequency ventilation.

Previous studies demonstrated that high-frequency oscillatory ventilation (HFOV) begun at birth limits the development of alveolar proteinaceous edema in premature monkeys at risk for hyaline membrane disease (HMD). We hypothesized that exogenous surfactant combined with HFOV would lead to even further reductions in edema. Twenty Macaca nemestrina monkeys were delivered at 134 d gestation (term = 168 d) and treated with either HFOV or conventional mechanical ventilation (CMV) from the first breath; modified bovine surfactant (Survanta [beractant]) was introduced into the trachea over the first few minutes of life. These animals were compared with 20 animals treated with either CMV or HFOV but without surfactant. At 6 h the lung was rapidly frozen in situ during inflation for determination of the volume fraction of alveolar edema. The combined use of surfactant and HFOV from the first breath reduced alveolar proteinaceous edema (3 +/- 1%; mean +/- SEM) from that seen with CMV alone (27 +/- 3%, p < 0.0001), CMV after surfactant (21 +/- 3%, p < 0.0001), and HFOV alone (13 +/- 3%, p < 0.015). We conclude that the use of surfactant with HFOV after premature birth is superior to either surfactant or HFOV alone in reducing lung injury during the first few hours of life. We speculate that this reduction in lung injury may reduce the incidence or severity of bronchopulmonary dysplasia.

Changes in hyaluronan deposition during early respiratory distress syndrome in premature monkeys.

Increased deposition of hyaluronan (HA) is part of the early response to fibrogenic stimulus in the lung exposed to bleomycin injury and has been associated with increased lung water in adult animals. Early respiratory distress syndrome (RDS) in premature infants is characterized by increased lung water, and late sequelae include fibrosis or bronchopulmonary dysplasia. We hypothesized that increased HA in the alveolar interstitium would be associated with increasingly severe RDS in prematurely delivered monkeys and that modes of therapy that affect severity of disease such as treatment with high-frequency oscillatory ventilation or exogenous surfactant would decrease this response. Thirty-four Macaca nemestrina monkeys were delivered at 134 +/- 1 d (term = 168 d) and randomized to high-frequency oscillatory ventilation or conventional mechanical ventilation from birth. Sixteen of these animals received surfactant. At 6 h of age, the right lower lung was frozen in situ during inflation to 30 cm H2O (approximately 2940 Pa) and then dehydrated and processed for microscopy. The presence and severity of RDS were evaluated by clinical and morphologic criteria. HA concentrations in lung extracts increased with progressively severe RDS (p = 0.0003). Treatment with high-frequency oscillatory ventilation decreased the lung injury score (1.69 +/- 0.7 compared with 2.5 +/- 0.9, p = 0.05), but changes in lung HA concentration did not reach significance (37.9 +/- 22.7 compared with 44.8 +/- 22.6). Surfactant treatment decreased lung HA concentration (29.6 +/- 19.0 micrograms/wet lung) compared with non-surfactant-treated animals (54.7 +/- 20.2 micrograms/g wet lung, p = 0.0009).(ABSTRACT TRUNCATED AT 250 WORDS)

Alternative modes of ventilation in the prevention and treatment of bronchopulmonary dysplasia.

Recent technologic innovations and refinements have increased and enhanced the armamentarium that potentially can prevent or ameliorate bronchopulmonary dysplasia. Short of altering the most important factor in the development of BPD--premature delivery--these new tools should allow individualization of ventilator treatment plans with a degree of sophistication not previously possible. By so doing, these techniques may shorten the often prolonged and uncertain course of recovery from BPD, and by so doing, limit the ongoing injury associated with BPD. The results of studies designed to test the utility of this new technology in the management of BPD are eagerly awaited.

Estimation of mortality risk in chronically ventilated infants with bronchopulmonary dysplasia.

Bronchopulmonary dysplasia is a chronic, sometimes fatal lung disease, which primarily affects premature infants and often leads to a dependence on mechanical ventilation lasting many months. To identify prognostic factors of mortality at 1 and 2 months of age, the authors reviewed the medical records of the 144 neonates admitted to two neonatal intensive care units in Seattle from January 1, 1986, through December 31, 1988, who required mechanical ventilation throughout the first month of life. Likely predictors of mortality were tested by logistic regression analysis. The calculated mean airway pressure at 30 days of age (MAP30) and the diagnosis of bacterial sepsis at any time during the first month of life (Bact 0-30) were statistically significant predictors of mortality (P less than .001 and P = .018, respectively) and had the lowest deviance in the regression model. The probability of mortality was estimated by 1/(1 + e-chi), where chi = -6.510 + 0.4588 (MAP30) + 1.475 (Bact 0-30), and where MAP30 is expressed as centimeters of water pressure (1 cm H2O = 0.0978 kPa) and the presence or absence of bacteremia is 1 and 0, respectively. The records of the 57 infants who still required mechanical ventilation at 60 days of age were reanalyzed with clinical data available during the first 2 months of life. Mean airway pressure (MAP 60) and the fraction of inspired oxygen (F60) at 60 days of age combined to form the best predictors of mortality, where chi = 7.668 + 0.2940 (MAP 60) + 5.935 (F60).(ABSTRACT TRUNCATED AT 250 WORDS)

Improved neonatal survival following multiple doses of bovine surfactant in very premature neonates at risk for respiratory distress syndrome.

To determine whether multiple doses of bovine surfactant would improve neonatal mortality in very premature neonates, we conducted two multicenter controlled trials under identical protocols; the results were combined for analysis. Four hundred and thirty neonates born between 23 and 29 weeks gestation and weighing 600 to 1250 g at birth were assigned randomly at birth to receive either 100 mg of phospholipids/kg of Survanta, a modified bovine surfactant (n = 210), or a sham air placebo (n = 220) within 15 minutes of birth. Neonates who developed respiratory distress syndrome and required mechanical ventilation with at least 30% oxygen could be given up to three more doses in the first 48 hours after birth. Dosing was performed by investigators not involved in the clinical care of the neonates; nursery staff were kept blinded as to the treatment assignment. Cause of death was determined by a panel of three independent, board-certified neonatologists after blindly reviewing case report forms and autopsy reports. Fewer Survanta-treated neonates died of any cause (11.4% vs 18.8%, P = .031), died of respiratory distress syndrome (1.9% vs 15.6%, P less than .001), and either died or developed bronchopulmonary dysplasia due to respiratory distress syndrome (39.5% vs 49.1%, P = .044). The incidence of respiratory distress syndrome was also lower in Survanta-treated neonates (28.0% vs 56.9%, P less than .001), and the Survanta-treated neonates' oxygenation and ventilatory status were improved significantly at 72 hours. Survanta-treated neonates were also at lowered risk of developing pulmonary interstitial emphysema (23.3% vs 36.9%, P = .002) and other forms of pulmonary air leaks (9.6% vs 20.8%, P .002).(ABSTRACT TRUNCATED AT 250 WORDS)

Predictors of neurodevelopmental outcome following bronchopulmonary dysplasia.

In infants with bronchopulmonary dysplasia, the influence of the severity of their pulmonary disease on neurodevelopmental outcome is unknown. Neurodevelopmental outcomes at a mean age of 36 months were assessed in 27 premature subjects who had bronchopulmonary dysplasia. Subjects had a mean birth weight of 940 g (range, 540 to 1690 g) and a mean gestational age of 27 weeks (range, 25 to 31 weeks). The duration of mechanical ventilation ranged from 22 to 128 days, and the duration of requirement of supplemental oxygen ranged from 34 to 1033 days. No significant correlations were found between duration of mechanical ventilation or oxygen therapy and overall neurodevelopmental outcome. In contrast, cranial ultrasound findings of intracranial hemorrhage and/or periventricular echodensity related specifically to poorer cognitive outcome. By age 3 years, severity of bronchopulmonary dysplasia is not a sufficient predictor of neurodevelopmental outcome. Intracranial hemorrhage and periventricular echodensity continue to be important predictors.

Fetal and maternal considerations in the management of stage I-B cervical cancer during pregnancy.

The timing of treatment for stage I-B cervical carcinoma diagnosed during pregnancy is complicated by conflicting concerns for fetal survival and control of malignancy. There were 11 pregnant women with stage I-B cervical carcinoma diagnosed prior to fetal viability since 1969. Six patients were managed with termination of pregnancy and radical hysterectomy with pelvic lymphadenectomy. In 5 patients, treatment was delayed for 6 to 17 weeks and then delivery was accomplished by cesarean section followed directly by radical hysterectomy and pelvic lymphadenectomy. Two of the infants experienced complicated neonatal courses and would have benefited from additional delay. Benefits that could be achieved by delaying delivery for the fetus were calculated from a review of 600 inborn infants without congenital anomalies admitted to the neonatal intensive care (NICU) during 1984 and 1985. Neonatal mortality decreased from 32.8% at 26-27 weeks to 2.7% at 34-35 weeks gestation. Similar improvements in neonatal morbidity were demonstrated. Although adverse maternal outcomes were not associated with delay, an evaluation of risk cannot be derived from this series. Significant fetal benefit can accrue from relatively short delays in planned delivery dates. When stage I-B cervical carcinoma is diagnosed during pregnancy and when fetal survival is desired, delivery should be delayed to achieve fetal maturity, rather than only potential viability.

Effects of hyperoxia and dimethylthiourea on neonatal pulmonary hemodynamics in piglets.

Exposure of piglets to 68-72 h of hyperoxia has previously been shown to blunt hypoxic pulmonary vasoconstriction (HPV). We tested the hypothesis that the administration of a scavenger of toxic oxygen radicals during exposure to hyperoxia would preserve HPV in piglets. Newborn piglets were kept in FIO2 greater than 0.90 for 68-72 h and compared to control animals kept in room air. Randomly selected animals from both groups were given the O2 metabolite scavenger, dimethylthiourea (DMTU) (500 mg/kg followed by 250 mg/kg/d), resulting in plasma levels of 2-6 mM. Following the oxygen or room air (RA) exposure period, piglets had pulmonary vascular resistance (PVR) measured following a 20 min exposure to alveolar hypoxia (FIO2 = 0.12). Both groups of RA-exposed animals (DMTU and saline treatment) as well as the hyperoxia-exposed saline group had almost 2-fold increases in PVR during exposure to hypoxia (P less than 0.05). Contrary to expectations, the PVR in the hyperoxia-exposed DMTU group did not rise significantly during hypoxia and the use of DMTU did not restore HPV by increasing PVR to levels greater than the hyperoxia/saline group (P = 0.70). Therefore DMTU does not appear to prevent hyperoxia-induced blunting of HPV in piglets.