Long-term trends in the incidence of congenital anomalies in Central China from 1997 to 2019.

OBJECTIVE: The aim of the study was to investigate the incidence of, and trends in, congenital anomalies in Central China from 1997 to 2019. STUDY DESIGN: This was a descriptive study. METHODS: We collected data describing 4,134,098 births from 75 hospital monitoring sites in Henan Province, Central China, from 1997 to 2019. A joinpoint regression model was used to analyze the continuous changes. RESULTS: There were 4,134,098 births recorded from 1997 to 2019, of which 50,646 noted the presence of congenital anomalies (incidence: 122.5 per 10,000). The incidence of congenital anomalies was found to have increased over time (P-trend <0.05). Congenital anomaly incidence in urban areas was higher than that in rural areas (155.3 per 10,000 vs 100.7 per 10,000; P < 0.001). Moreover, incidence was higher in males than in females (129.1 per 10,000 vs 112.9 per 10,000; P < 0.001). The incidence of neural tube defects significantly reduced from 1997 to 2019 (39.3 per 10,000 in 1997 vs 0.92 per 10,000 in 2019, P-trend <0.001), whereas the incidence of congenital heart disease (CHD) increased (5.56 per 10,000 in 2010 to 136.46 per 10,000 in 2019), which meant that CHD was the most common congenital anomaly post-2013. CONCLUSION: In Henan province, the incidence of congenital anomalies increased by 115% from 1997 to 2019. Notably, the incidence of CHD is rising.

[Comparison of the efficacy of irreversible electroporation and conversional resection for locally advanced pancreatic cancer].

Objective: To compare the short-term and long-term prognosis of irreversible electroporation(IRE) and conversional resection for locally advanced pancreatic cancer(LAPC). Methods: The clinical and pathological data of 98 LAPC patients who underwent IRE or conversional resection at the Department of Pancreatobiliary Surgery,Sun Yat-sen University Cancer Center from August 2015 to December 2020 were retrospectively collected and analyzed.The study comprised of 53 males and 45 females, with age(M(IQR)) of 57.5(13.5)years old(range:20 to 87 years old). Fifty-three patients received IRE treatment(IRE group) and 45 patients received surgical resection(resection group). The differences of clinical and pathological data between both groups were not significant(all P<0.05). The Mann-Whitney U test was used for quantitative data and the χ2 test was used for categorical data.Survival was analyzed using Kaplan-Meier method and compared using Log-rank test. Results: The operation time and intraoperative blood loss were 5.0(2.4)hours and 50(100) ml in the IRE group,respectively,which were significantly less than those of resection group(7.0(3.3)hours and 400(200)ml,both P<0.05).The hospital stay and hospitalization cost were 9.0(3.0)days and 79 154 (83 738) yuan in the IRE group,respectively,which were also significantly less than those in the resection group(16.0(8.5)days and 109 557(37 795)yuan,both P<0.05).The complication rate of IRE group was significantly lower than that of the resection group(18.8% vs. 55.6%,χ2=14.270,P<0.01).The median overall survival(OS) time of IRE group was 28.9 months(95%CI:23.2 to 34.6 months),with the 1-,2-,and 3-year OS rates of 91.6%,61.7%,and 24.6%,respectively.The median survival of OS of resection group was 27.1 months(95%CI:20.9 to 33.3 months),with the 1-,2-,and 3-year OS rates of 81.8%,53.9%,and 30.3%,respectively.There was no significant difference in OS between the two groups(χ2=0.900,P=0.760).The median progression free survival(PFS) time of IRE group was 18.0 months(95%CI:14.7 to 21.3 months),with the 1-,2-,and 3-year PFS rates of 68.3%,29.7%,and 9.9%,respectively.The median survival of PFS of resection group was 11.1 months(95%CI:6.1 to 16.2 months),with the 1-,2-,and 3-year PFS rates of 45.2%,21.9%,and 14.6%,respectively.There was no significant difference in PFS between the two groups(χ2=1.850,P=0.170). Conclusion: IRE can achieve similar survival for LAPC and may has less complications compared to those with conversion resection.

[Combining intraoperative ultrasound-guided irreversible electroporation with chemotherapy for treating locally advanced pancreatic cancer: a clinical report of 64 cases].

Objective: To examine the safety and clinical efficacy of ultrasound-guided irreversible electroporation (IRE) using the open surgery approach, after induction chemotherapy, in the treatment of locally advanced pancreatic cancer (LAPC) . Methods: The data of 64 LAPC patients who underwent ultrasound-guided IRE using the open surgery approach after induction chemotherapy at Department of Pancreatobiliary Surgery, Sun Yat-sen University Cancer Center from August 2015 to March 2019 were retrospectively analyzed. The study comprised of 30 males and 34 females, with median age of 58.5 years old (range: 34 to 87 years old) , were included in this study.The tumor was located in the pancreatic head and body/tail in 30 and 34 patients, respectively.The largest recorded tumor size was 6.1 cm (≤4.0 cm: n=35; >4.0 cm: n=29) .To create an electric field around the tumor, Two to six probes were parallelly inserted into each patient's tumor, based on the size of the tumor, at a distance of 2 cm apart through the transverse mesocolon in a caudal-to-cranial direction.According to the numerical sequence of patients undergoing ultrasound-guided IRE, the first 15 cases and following 49 patients were categorized as the primary and secondary treatment group, respectively.T text or χ(2) test was analyzed to the data between two groups.The study endpoints were overall survival (OS) and progression free survival (PFS) , which were investigated using Kaplan-Meier method, and their differences were compared using log-rank test. Results: The overall length of hospital stay was (8.9±2.7) days (range: 5 to 20 days) . Four patients were lost to follow-up.The study follow-up rate was 93.8%, with a median follow-up time of 29.3 months (range: 13.5 to 55.7 months) .The median OS and PFS of the entire cohort was 24.6 months (95% CI: 22.0 to 27.3 months) and 12.0 months (95%CI: 8.8 to 15.2 months) , respectively.One month after IRE, abdominal pain was significantly relieved in 95.3% of the patients (t=-28.55, P<0.01) .The rate of complications in the entire cohort was 20.3% and all were classified as grade B.Of them, pancreatic fistula, incisional infection, and upper gastrointestinal hemorrhage were observed in 7, 4, and 2 cases, respectively.The rate of complications for patients in the primary and secondary treatment groups were significantly different (10/15 vs. 6.1%) , respectively (χ(2)=26.01, P<0.01) .Further, two deaths were observed after IRE in the primary treatment group, while none was observed in the secondary treatment group. Conclusions: Ultrasound-guided IRE using the open surgery approach after induction chemotherapy is found to be safe and effective in treating patients with LAPC.However, these findings should be validated in prospective randomized trials before wide clinical application.

[Pilot study of the relationship between clinical classification of gallbladder cancer and prognosis: a retrospective multicenter clinical study].

Objectives: To propose a novel clinical classification system of gallbladder cancer, and to investigate the differences of clinicopathological characteristics and prognosis based on patients who underwent radical resection with different types of gallbladder cancer. Methods: The clinical data of 1 059 patients with gallbladder cancer underwent radical resection in 12 institutions in China from January 2013 to December 2017 were retrospectively collected and analyzed.There were 389 males and 670 females, aged (62.0±10.5)years(range:22-88 years).According to the location of tumor and the mode of invasion,the tumors were divided into peritoneal type, hepatic type, hepatic hilum type and mixed type, the surgical procedures were divided into regional radical resection and extended radical resection.The correlation between different types and T stage, N stage, vascular invasion, neural invasion, median survival time and surgical procedures were analyzed.Rates were compared by χ(2) test, survival analysis was carried by Kaplan-Meier and Log-rank test. Results: Regional radical resection was performed in 940 cases,including 81 cases in T1 stage,859 cases in T2-T4 stage,119 cases underwent extended radical resection;R0 resection was achieved in 990 cases(93.5%).The overall median survival time was 28 months.There were 81 patients in Tis-T1 stage and 978 patients in T2-T4 stage.The classification of gallbladder cancer in patients with T2-T4 stage: 345 cases(35.3%)of peritoneal type, 331 cases(33.8%) of hepatic type, 122 cases(12.5%) of hepatic hilum type and 180 cases(18.4%) of mixed type.T stage(χ(2)=288.60,P<0.01),N stage(χ(2)=68.10, P<0.01), vascular invasion(χ(2)=128.70, P<0.01)and neural invasion(χ(2)=54.30, P<0.01)were significantly correlated with the classification.The median survival time of peritoneal type,hepatic type,hepatic hilum type and mixed type was 48 months,21 months,16 months and 11 months,respectively(χ(2)=80.60,P<0.01).There was no significant difference in median survival time between regional radical resection and extended radical resection in the peritoneal type,hepatic type,hepatic hilum type and mixed type(all P>0.05). Conclusion: With application of new clinical classification, different types of gallbladder cancer are proved to be correlated with TNM stage, malignant biological behavior and prognosis, which will facilitate us in preoperative evaluation,surgical planning and prognosis evaluation.

Household cleaning products and the risk of allergic dermatitis: a prospective cohort study with primary-school children.

BACKGROUND: Household cleaning products are widely used by the public, but limited data have been obtained on whether their use induces allergic dermatitis in children. OBJECTIVE: This study investigated the association between exposure to household cleaning products and allergic dermatitis in primary-school children. METHODS: A prospective cohort study of Hong Kong primary-school children was conducted between 2012 and 2014. A baseline survey was administered to 1812 students who did not have allergic dermatitis. Information on respiratory symptoms, exposure to household chemical cleaning products and other topics was collected using a self-administered questionnaire. A cumulative chemical burden (CCB) score was calculated for each student by summing the duration of exposure to 14 chemical cleaning products. Principal component analysis was used to identify patterns in the use of these cleaning products. Logistic regression was performed to calculate relative risk (RR) with 95% confidence intervals (CIs) after adjusting for potential confounders. RESULTS: Eighty-nine (4.9%) of the students surveyed had dermatitis during the follow-up. However, exposure to individual chemical cleaning products was not found to be associated with the children's allergic dermatitis (all P > 0.05). In contrast to those in the lowest tertile, neither CCB scores in the middle tertile (RR: 1.16, 95% CI: 0.67 to 2.00) nor those in the highest tertile (RR: 1.24, 95% CI: 0.73 to 2.14) were significantly associated with the risk of allergic dermatitis. The adjusted RR for every 5-unit increment in CCB score was 1.01 (95% CI: 0.98 to 1.03). Four patterns of cleaning-product use were derived, but none were found to be associated with the risk of dermatitis (all P > 0.05). CONCLUSION: The use of household chemical cleaning products is not associated with the risk of dermatitis in primary-school children.

Spatiotemporal analysis of tuberculosis incidence and its associated factors in mainland China.

Spatiotemporal analysis is an important tool to monitor changes of tuberculosis (TB) epidemiology, identify high-risk regions and guide resource allocation. However, there are limited data on the contributing factors of TB incidence. This study aimed to investigate the spatiotemporal pattern of TB incidence and its associated factors in mainland China during 2005-2013. Global Moran's I test, Getis-Ord Gi index and heat maps were used to examine the spatial clustering and seasonal patterns. Generalized Linear Mixed Model was applied to identify factors associated with TB incidence. TB incidence presented high geographical variations with two main hot spots, while a generally consistent seasonal pattern was observed with a peak in late winter. Furthermore, we found province-level TB incidence increased with the proportion of the elderly but decreased with Gross Demographic Product per capita and the male:female ratio. Meteorological factors also influenced TB incidence. TB showed obvious spatial clustering in mainland China and both the demographic and socio-economic factors and meteorological measures were associated with TB incidence. These results provide the related information to identify the high-risk districts and the evidence for the government to develop corresponding control measures.

Overall obesity is leveling-off while abdominal obesity continues to rise in a Chinese population experiencing rapid economic development: analysis of serial cross-sectional health survey data 2002-2010.

BACKGROUND: Obesity epidemic is related to industrialization and urbanization that have lead to changes in nutrition, lifestyle and socio-economic status. However, information on the trajectory of the obesity epidemic in populations experiencing rapid economic development is limited. We therefore investigate trends in obesity from 2002 to 2010 in a southern Chinese population experiencing world's fastest economic development. METHODS: Between 2002 and 2010 four standardized surveys were conducted in a population of 85 million residents in Guangdong, China. Multistage cluster sampling was adopted to recruit representative samples. Weight, height and waist circumference of the participants were measured in a standardized way. The analysis included residents aged between 18 and 69 years. The number of participants included in the present analysis for Surveys conducted in 2002, 2004, 2007 and 2010 were 13058, 7646, 6441 and 8575, respectively. RESULTS: From year 2002 to 2010, the age-standardized Body mass index (BMI) insignificantly changed from 21.7 kg m(-2) to 22.3 kg m(-2), and the prevalence of overweight and overall obesity from 15.8 to 16.6% (both P>0.05). The age-standardized waist circumference increased from 73.7 to 78.4 cm, and prevalence of abdominal obesity increased from 12.9 to 23.7% (both P<0.001). In urban areas, BMI and overall obesity changed little during the 8-year period (BMI increased from 22.6 to 22.7 kg m(-2) and overall obesity changed from 23.7 to 21.4%), whereas there were slight increases of the same in rural areas (BMI increased from 20.8 to 22.1 kg m(-2)and overall obesity increased from 8.2 to 13.3%). Waist circumference and abdominal obesity increased significantly in both areas, but the increase was more pronounced in rural areas (in urban area, waist circumference increased from 75.1 to 78.5 cm and abdominal obesity from 16.8 to 26.5%; in rural area, waist circumference from 72.2 to 78.3 and abdominal obesity from 8.8 to 22.0%). CONCLUSIONS: BMI and overall obesity in this population, which has experienced the world's fastest economic development over the past three decades, has been leveling-off, while waist circumference and abdominal obesity, independent predictors of cardiovascular risk, have continued to rise. Our findings suggest that obesity epidemic transition in rapidly developing populations may be much faster than what has been observed in Western countries.

[Analysis on infection risk in secondary close contacts of COVID-19 patients].

Objective: To study the infection rate of secondary close contacts of COVID-19 patients, and assess the infection risk in the contacts. Methods: COVID-19 patients' close contacts (with a clear exposure time to index case) with negative nucleic acid test results and secondary close contacts were surveyed in continuous isolation and medical observation in this prospective study. The dynamic nucleic acid test results of the close contacts and secondary contacts of COVID-19 patients were collected to assess their risk of infection. Results: A total of 4 533 close contacts were surveyed, in whom 14 were confirmed as COVID-19 patients with overall secondary attack rate of 0.31%, and 4 201 secondary contacts were tracked, in whom no subsequent infections occurred. Conclusion: Close contacts of COVID-19 patients entered in centralized isolation for medical observation with negative nucleic acid tese results,the secondary close contacts of COVID-19 patients have no risk of infection.

[Analysis on infectivity of COVID-19 patients before and after last negative nucleic acid test].

Objective: To investigate the infection rate in close contacts of COVID-19 patients before and after the last negative nucleic acid test, evaluate the effect of dynamic nucleic acid test in determining the infectivity of COVID-19 patients. Methods: Dynamic nucleic acid test results of COVID-19 cases were collected in a retrospective cohort study. COVID-19 cases with negative nucleic acid test results before their first positive nucleic acid tests were selected as study subjects. Close contacts of the index cases and the secondary close contacts were kept isolation for medical observation to assess their risk of infection. Results: This study included 89 confirmed cases from two local COVID-19 epidemics in Ningbo. A total of 5 609 close contacts were surveyed, the overall infection rate was 0.20%. No close contacts of the COVID-19 cases before the last negative nucleic acid test were infected, and the infection rate in the close contacts of the COVID-19 cases after the last negative nucleic acid test was 1.33%, all of these close contacts lived together with the index cases. No secondary close contacts were infected. Conclusion: COVID-19 patient becomes infectious after the last nucleic acid is negative, and has no infectivity before the last nucleic acid negative.

Sex and age differences in lipid response to chronic infection with the hepatitis C virus in the United States National Health and Nutrition Examination Surveys.

Low levels of serum lipids were reported in subjects chronically infected with the hepatitis C virus (HCV) and correlated with poorer clinical outcomes. Whether HCV 'hypo-lipidemia' is constant across age, sex and race has not been systematically explored. We therefore investigated the association between HCV infection and serum lipid levels in two independent National Health and Nutrition Examination Survey (NHANES) cohorts. HCV antibody status and serum lipid levels were obtained from 14 369 adults from NHANES 1999-2006 and 12 261 from NHANES III (enrolled in 1988-1994). In multivariable models, the prevalence of HCV-associated hypo-low density lipoprotein-cholesterol was highest among women >50 years of age in both NHANES 1999-2006 (OR: 10.51, 95% CI: 2.86, 38.62) and III (OR: 24.21, 95% CI: 6.17, 94.92), but among women <50 years of age, the odds ratios were 3.01 (95% CI: 1.00, 9.04) for NHANES 1999-2006 and 0.52 (95% CI: 0.14, 1.88) for III, respectively. HCV by age interaction among women was significant in both cohorts (P < 0.001 and P = 0.004, respectively). Among men, the odds ratios of HCV-associated hypo-LDL-cholesterol were 2.74 (95% CI: 1.55, 4.85) in NHANES 1999-2006 and 3.84 (95% CI: 1.66, 8.88) in III, respectively, with no significant age effects. Similar patterns were observed for total-cholesterol, but no significantly discernable patterns for high density lipoprotein-cholesterol and triglycerides. Results show that HCV infection is associated with lower total- and LDL-cholesterol in two US population-based cohorts, and this relationship varies significantly by age and sex, suggesting a possible influence of sex hormones on host lipid response to HCV infection.

Sporophytic self-incompatibility genes and mating system variation in Arabis alpina.

BACKGROUND AND AIMS: Sporophytic self-incompatibility (SI) prevents inbreeding in many members of the Brassicaceae, and has been well documented in a variety of high-profile species. Arabis alpina is currently being developed as a model system for studying the ecological genetics of arctic-alpine environments, and is the focus of numerous studies on population structure and alpine phylogeography. Although it is highly inbreeding throughout most of its range, populations in central Italy have been identified that show inbreeding coefficients (F(IS)) more typical of self-incompatible relatives. The purpose of this study was to establish whether this variation is due to a functioning SI system. METHODS: Outcrossing rate estimates were calculated based on 16 allozyme loci and self-compatibility assessed based on controlled pollinations for six Italian populations that have previously been shown to vary in F(IS) values. Putative SRK alleles (the gene controlling the female component of SI in other Brassicaceae) amplified from A. alpina were compared with those published for other species. Linkage of putative SRK alleles and SI phenotypes was assessed using a diallel cross. KEY RESULTS: Functional avoidance of inbreeding is demonstrated in three populations of A. alpina, corresponding with previous F(IS) values. The presence is described of 15 putative SRK-like alleles, which show high sequence identity to known alleles from Brassica and Arabidopsis and the high levels of synonymous and nonsynonymous variation typical of genes under balancing selection. Also, orthologues of two other members of the S-receptor kinase gene family, Aly8 (ARK3) and Aly9 (AtS1) are identified. Further to this, co-segregation between some of the putative S-alleles and compatibility phenotypes was demonstrated using a full-sibling cross design. CONCLUSIONS: The results strongly suggest that, as with other species in the Brassicaceae, A. alpina has a sporophytic SI system but shows variation in the strength of SI within and between populations.

The impact of particulate matter air pollution (PM2.5) on atherosclerosis in modernizing China: a report from the CATHAY study.

BACKGROUND: Air pollution has been associated with an increase in cardiovascular diseases incidence. To evaluate whether air pollution can accelerate atherogenic processes, we assessed the effects of air pollution on important surrogate markers of atherosclerosis [brachial flow-mediated dilation (FMD) and carotid intima-media thickness (IMT)]. METHODS: A total of 1656 Han Chinese (mean age 46.0 + 11.2 years; male 47%) in Hong Kong, Macau, Pun Yu, Yu County and the 3-Gorges Territories (Yangtze River) were studied between 1996 and 2007 [Chinese Atherosclerosis in the Aged and Young Project (the CATHAY Study)]. Cardiovascular risk profiles were evaluated. Particulate matter with an aerodynamic diameter <2.5 µm (PM2.5) parameters were computed from satellite sensors. Brachial FMD and carotid IMT were measured by ultrasound. RESULTS: Health parameters [age, gender, body mass index, waist : hip ratio (WHR) and glucose)] were similar in lowest and highest PM2.5 exposure tertiles, systolic and diastolic blood pressures and triglycerides were higher (P < 0.001) and low-density cholesterol (LDL-C) was lower in the top PM2.5 tertile (P < 0.001). Brachial FMD [7.84 ± 1.77, 95% confidence interval (CI) 7.59-8.10%, vs 8.50 ± 2.52, 95% CI 8.23-8.77%, P < 0.0001) was significantly lower and carotid IMT (0.68 ± 0.13 mm, 95% CI 0.67-0.69 mm vs 0.63 mm ± 0.15 mm 95% CI 0.62-0.64 mm; P < 0.0001) was significantly thicker in the top PM2.5 tertile compared with the lowest tertile. On multiple regression, FMD was inversely related to PM2.5 (beta = 0.134, P = 0.015) independent of gender, age and blood pressure (model R2 = 0.156, F-value = 7.6, P < 0.0001). Carotid IMT was significantly correlated with PM2.5 exposure (beta = 0.381, P < 0.0001) independent of age, location, gender, WHR, blood pressure and LDL-C (model R2 = 0.408, F-value = 51.4, P-value <0.0001). CONCLUSIONS: Air pollution is strongly associated with markers of early atherosclerosis, suggesting a potential target for preventive intervention.

Diagnostic value of intraoperative bone marrow assessment for bone margins in patients with head and neck squamous cell carcinoma: a systematic review and meta-analysis.

A clear bone margin is essential for complete resection of the bone-involved tumour, but the evaluation of hard tissue takes time and is impractical intraoperatively. Bone marrow assessment remains controversial. The aim of this study was to investigate the diagnostic value of intraoperative bone marrow assessment for bone margins. PubMed and Web of Science were searched for studies published between 1990 and 2017. A systematic review was conducted. After quality assessment, 10 articles with 11 cohorts and 404 patients were identified. Sensitivity, specificity, and other measures were pooled for meta-analysis; the estimates for intraoperative bone marrow assessment were as follows: sensitivity 0.82 (95% confidence interval (CI) 0.62-0.93), specificity 0.99 (95% CI 0.96-1.00), positive likelihood ratio 109.79 (95% CI 22.99-524.34), negative likelihood ratio 0.18 (95% CI 0.08-0.42), and diagnostic odds ratio 241.82 (95% CI 90.33-647.38). Furthermore, sensitivity and specificity at the summary operating point of the summary receiver operating characteristic curve were 0.82 and 0.99, respectively, and the area under the curve was 0.99. Intraoperative bone marrow assessment was investigated by meta-analysis and shown to have a high level of overall accuracy for the diagnosis of bone margins.

Threshold-type dose response for induction of neoplastic transformation by 1 GeV/nucleon iron ions.

Neoplastic transformation of HeLa x skin fibroblast human hybrid cells by doses of 1 GeV/nucleon iron ions in the range 1 cGy to 1 Gy to exposed cultures has been examined. The data indicate a threshold-type dose-response curve with no increase in transformation frequency until doses above 20 cGy. At doses <10 cGy, not all exposed cells receive a direct traversal of an iron-ion track core, but all exposed cells receive up to several mGy of low-LET radiation associated with the delta-ray penumbra. It is proposed that the threshold-type response seen is a consequence of an adaptive response associated with the delta-ray exposure. For comparison purposes, the dose response for (137)Cs gamma rays over the same dose range was examined using the same experimental procedure. As we have shown previously, the dose response for (137)Cs gamma radiation was J-shaped. The iron ions were 1.5 to 1.7 times more biologically effective than the gamma radiation over the dose range examined.

Low doses of very low-dose-rate low-LET radiation suppress radiation-induced neoplastic transformation in vitro and induce an adaptive response.

The purpose of this study was to determine whether adaptation against neoplastic transformation could be induced by exposure to very low-dose-rate low-LET radiation. HeLa x skin fibroblast human hybrid cells were irradiated with approximately 30 kVp photons from an array of (125)I seeds. The initial dose rate was 4 mGy/day. Cell samples were taken at four intervals at various times over a period of 88 days and assayed for neoplastic transformation and the presence of reactive oxygen species (ROS). The dose rate at the end of this treatment period was 1.4 mGy/day. Transformation frequencies and ROS levels were compared to those of parallel unirradiated controls. At the end of 3 months and an accumulated dose of 216 mGy, cells treated with very low-dose-rate radiation were exposed to a high-dose-rate 3-Gy challenge dose of (137)Cs gamma rays, and the effects compared with the effect of 3 Gy on a parallel culture of previously unirradiated cells. Cells exposed to very low-dose-rate radiation exhibited a trend toward a reduction in neoplastic transformation frequency compared to the unirradiated controls. This reduction seemed to diminish with time, indicating that the dose rate, rather than accumulated dose, may be the more important factor in eliciting an adaptive response. This pattern was in general paralleled by a reduction of ROS present in the irradiated cultures compared to controls. The very low-dose-rate-treated cells were less sensitive to the high challenge dose than unirradiated controls, suggesting the induction of an adaptive response. Since there was a suggestion of a dose-rate threshold for induction suppression, a second experiment was run with a fresh batch of cells at an initial dose rate of 1 mGy/day. These cells were allowed to accumulate 40 mGy over 46 days (average dose rate=0.87 mGy/day), and there was no evidence for suppression of transformation frequency compared to parallel unirradiated controls. It is concluded that doses of less than 100 mGy delivered at very low dose rates in the range 1 to 4 mGy/day can induce an adaptive response against neoplastic transformation in vitro. When the dose rate drops below approximately 1 mGy/day, this suppression is apparently lost, suggesting a possible dose-rate-dependent threshold for this process.

[Sinus syndrome, an uncommon cause of enophthalmos]. / Síndrome del seno silente, una causa infrecuente de enoftalmos.

CLINICAL CASE: A 29-year-old woman presented with a subjective sensation of ocular asymmetry from several months beforehand. Ophthalmological exam showed 3,5 mm right enophthalmos and light hypoglobus. CT (Computerized Tomography) scan showed a collapsed maxillar sinus, and a thinned inferior orbital wall. The diagnosis of silent sinus syndrome was made. An endoscopic maxillary antrostomy with uncinectomy was made with an excellent surgical outcome. DISCUSSION: Clinical features of silent sinus syndrome are described, including diagnosis, differential diagnosis and treatment.