[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.

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.

[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.

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.

[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.

The incidence of cancer deaths among hypertensive patients in a large Chinese population: a cohort study.

Current evidence is mixed regarding the association between antihypertensive prescriptions and cancer mortality. We evaluated this association in a large Chinese hypertensive population. We followed for five years all patients who were prescribed their first-ever antihypertensive agents between 2001 and 2005 in a public healthcare sector of Hong Kong. The association between antihypertensive drug class and cancer mortality was evaluated by Cox proportional hazard models with propensity score matching. Age, gender, socioeconomic status, service settings, district of residence, proportion of days covered reflecting medication adherence, and the number of comorbidities were adjusted. From 217,910 eligible patients, 9500 (4.4%) died from cancer within five years after their first-ever antihypertensive prescription. Most cancer deaths occurred in the digestive (38.9%) and respiratory system (30.4%); the breast (6.2%); and the lympho-hematopoietic tissues (5.3%). The proportion of patients who died from cancer was the highest in the calcium channel blocker (CCB) group (6.5%), followed by thiazide diuretics (4.4%), angiotensin converting enzyme inhibitors (4.2%) and ß-blockers (2.6%). When compared with ß-blockers, patients prescribed CCBs (Adjusted Hazard Ratio [AHR]=1.406, 95% C.I. 1.334-1.482, p<0.001) were more likely to die from cancer. Thiazide users were also more likely to suffer from cancer deaths (AHR=1.364, 95% C.I. 1.255-1.483, p<0.001), but became insignificant in stratified analysis. The association between cancer mortality and use of CCB, and perhaps thaizide, may alert physicians to the need for more meticulous and comprehensive care of these patients in clinical practice. We recommend prospective studies to evaluate cause-and-effect relationships of these associations.

Hepatic resection for synchronous hepatic metastasis from gastric cancer.

BACKGROUND: The role of surgical resection for synchronous hepatic metastases arising from gastric adenocarcinoma has not been established. This study was designed to explore the clinicopathologic features and surgical results of these patients. METHODS: Twenty-five (4.8%) of 526 patients diagnosed with synchronous hepatic metastatic gastric cancer received hepatectomy and gastrectomy at the same time; 2 cases underwent repeat hepatectomy after intrahepatic recurrence. Clinicopathologic parameters of the hepatic metastases and the surgical results for all 25 patients were analysed. RESULTS: The 1-, 3-, and 5-year overall survival (OS) and recurrence-free survival (RFS) rates after resection were 96.0%, 70.4%, and 29.4%, respectively, and 56.0%, 22.3%, and 11.1%, respectively. Five patients survived for more than 5 years after surgery, and no mortality has occurred within 30 days after resection. Univariate analysis revealed that patients with multiple hepatic metastases suffered poorer OS (P = 0.026) and RFS (P = 0.035) than those with solitary hepatic metastasis. Postoperative adjuvant chemotherapy was a significant indicator of a favourable OS (P = 0.022). Number of metastatic lesions remained significant in the multivariate analysis of OS and RFS (P = 0.039, P = 0.049, respectively). None of variables of the primary lesion was a significant prognostic factor for those patients. CONCLUSIONS: Gastric cancer patients with a solitary synchronous liver metastasis may be good candidates for hepatic resection. Postoperative adjuvant chemotherapy may provide a benefit by aiding in OS.

Neoplastic transformation in vitro by mixed beams of high-energy iron ions and protons.

The radiation environment in space is complex in terms of both the variety of charged particles and their dose rates. Simulation of such an environment for experimental studies is technically very difficult. However, with the variety of beams available at the National Space Research Laboratory (NSRL) at Brookhaven National Laboratory (BNL) it is possible to ask questions about potential interactions of these radiations. In this study, the end point examined was transformation in vitro from a preneoplastic to a neoplastic phenotype. The effects of 1 GeV/n iron ions and 1 GeV/n protons alone provided strong evidence for suppression of transformation at doses ≤5 cGy. These ions were also studied in combination in so-called mixed-beam experiments. The specific protocols were a low dose (10 cGy) of protons followed after either 5-15 min (immediate) or 16-24 h (delayed) by 1 Gy of iron ions and a low dose (10 cGy) of iron ions followed after either 5-15 min or 16-24 h by 1 Gy of protons. Within experimental error the results indicated an additive interaction under all conditions with no evidence of an adaptive response, with the one possible exception of 10 cGy iron ions followed immediately by 1 Gy protons. A similar challenge dose protocol was also used in single-beam studies to test for adaptive responses induced by 232 MeV/n protons and (137)Cs γ radiation and, contrary to expectations, none were observed. However, subsequent tests of 10 cGy of (137)Cs γ radiation followed after either 5-15 min or 8 h by 1 Gy of (137)Cs γ radiation did demonstrate an adaptive response at 8 h, pointing out the importance of the interval between adapting and challenge dose. Furthermore, the dose-response data for each ion alone indicate that the initial adapting dose of 10 cGy used in the mixed-beam setting may have been too high to see any potential adaptive response.

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.

The effect of dose rate on radiation-induced neoplastic transformation in vitro by low doses of low-LET radiation.

The dependence of the incidence of radiation-induced cancer on the dose rate of the radiation exposure is a question of considerable importance to the estimation of risk of cancer induction by low-dose-rate radiation. Currently a dose and dose-rate effectiveness factor (DDREF) is used to convert high-dose-rate risk estimates to low dose rates. In this study, the end point of neoplastic transformation in vitro has been used to explore this question. It has been shown previously that for low doses of low-LET radiation delivered at high dose rates, there is a suppression of neoplastic transformation frequency at doses less than around 100 mGy. In the present study, dose-response curves up to a total dose of 1000 mGy have been generated for photons from (125)I decay (approximately 30 keV) delivered at doses rates of 0.19, 0.47, 0.91 and 1.9 mGy/min. The results indicate that at dose rates of 1.9 and 0.91 mGy/min the slope of the induction curve is about 1.5 times less than that measured at high dose rate in previous studies with a similar quality of radiation (28 kVp mammographic energy X rays). In the dose region of 0 to 100 mGy, the data were equally well fitted by a threshold or linear no-threshold model. At dose rates of 0.19 and 0.47 mGy/min there was no induction of transformation even at doses up to 1000 mGy, and there was evidence for a possible suppressive effect. These results show that for this in vitro end point the DDREF is very dependent on dose rate and at very low doses and dose rates approaches infinity. The relative risks for the in vitro data compare well with those from epidemiological studies of breast cancer induction by low- and high-dose-rate radiation.

Parity and the metabolic syndrome in older Chinese women: the Guangzhou Biobank Cohort Study.

OBJECTIVE: To examine whether parity or gravidity contributes to the development of the metabolic syndrome (MS). METHODS: The first phase of the Guangzhou Biobank Cohort Study recruited 7352 women and 3065 men aged 50-93 years in 2003-4. Data on the number of live births and pregnancies, other reproduction-associated factors and socioeconomic and lifestyles factors were collected by standardized interview. The MS components were determined through physical examination and measurement of fasting blood samples. MS was identified if waist circumference was >or= 90 cm for men or >or= 80 cm for women, plus any two of: (a) raised triglyceride (TG) level (1.7 mmol/l) or specific treatment for this lipid abnormality; (b) reduced high density lipoprotein (HDL)-cholesterol (< 1.03 mmol/l in males or < 1.29 mmol/l in females) or specific treatment for this lipid abnormality; (c) raised blood pressure (BP, systolic BP >or= 130 mmHg or diastolic BP >or= 85 mmHg) or hypertension therapy; and (d) raised fasting glucose (>or= 5.6 mmol/l) or previously diagnosed type 2 diabetes. RESULTS: Before adjustment for potential confounders, we found associations between the number of births and lifestyle and socioeconomic factors in both sexes. However, in women, but not in men, body mass index (BMI), waist-hip ratio, triglyceride and glucose were positively associated with the number of birth after adjusting for a range of potential confounders. The age-adjusted prevalence of the MS increased with the number of births and pregnancies in women, but the gradient for birth was steeper than that for pregnancies [odds ratio change per birth 1.16, 95% confidence interval (CI) 1.11-1.22, P < 0.001; odds ratio change per pregnancy 1.11, 95% CI 1.06-1.16, P < 0.001], although attenuating the association adjustment did not affect the significance of these findings. There was no association in men with regard to the number of their partners' live births given the same analysis and similar shared living background with the women. CONCLUSION: Higher parity or gravidity was associated with a consistent increase in the risk of MS in Chinese women. As the association persisted after adjustment for lifestyle factors and there was no association between the risk of MS and the number of births associated with the partners of the males, the association in women may represent a biological response to pregnancy.

Snoring and vascular risk factors and disease in a low-risk Chinese population: the Guangzhou Biobank Cohort Study.

STUDY OBJECTIVE: Snoring is a common condition, but data describing the relationship between snoring and vascular disease is very limited in Asian populations. We therefore describe the association between snoring and vascular disease and associated risk factors. DESIGN: Cross-sectional study of baseline data from the Guangzhou Biobank Cohort Study. SETTING: Community-based elderly association from Guangzhou, China. PARTICIPANTS: 10413 Chinese subjects (50-85 years of age). MEASUREMENTS: Self-reported snoring status and frequency and frequency of daytime tiredness were collected by questionnaire, as were demographic and socioeconomic data, disease histories, and potential confounders, such as smoking and alcohol consumption. Anthropometry, blood pressure, and fasting glucose and lipid profile were also measured. RESULTS: Self-reported snoring frequency was identified in 8325 (80.0%) subjects, with 51.6% reporting that they snored, of whom 15.5% were daily snorers. Increasing prevalence of snoring showed a clear positive relationship with cardiovascular risk factors, including age, obesity, blood pressure, and lipid levels (p < .001 for all). The prevalence of self-reported vascular-disease history was low but significantly associated with increasing snoring frequency. Logistic regression showed that snoring frequency was an independent predictor of vascular-disease history (odds ratios [95% confidence intervals] 1.68 [1.32-2.13] for daily snorers compared with the never-snorer reference group), of the metabolic syndrome (2.16 [1.88-2.49]) and each of its components (hypertension [1.37 (1.20-1.56)], and of dyslipidemia [1.22 (1.07-1.40)], central obesity [2.39 (2.08-2.76)], and diabetes [1.30 (1.09-1.56)]) after adjustment for potential confounders. CONCLUSION: Increasing snoring frequency was associated with an increasing prevalence of risk factors and self-reported vascular disease. Snoring may a useful marker for increased risk of vascular disease.

Neoplastic transformation in vitro by low doses of ionizing radiation: role of adaptive response and bystander effects.

The shape of the dose-response curve for cancer induction by low doses of ionizing radiation is of critical importance to the assessment of cancer risk at such doses. Epidemiologic analyses are limited by sensitivity to doses typically greater than 50-100 mGy for low LET radiation. Laboratory studies allow for the examination of lower doses using cancer-relevant endpoints. One such endpoint is neoplastic transformation in vitro. It is known that this endpoint is responsive to both adaptive response and bystander effects. The relative balance of these processes is likely to play an important role in determining the shape of the dose-response curve at low doses. A factor that may influence this balance is cell density at time of irradiation. The findings reported in this paper indicate that the transformation suppressive effect of low doses previously seen following irradiation of sub-confluent cultures, and attributed to an adaptive response, is reduced for irradiated confluent cultures. However, even under these conditions designed to optimize the role of bystander effects the data do not fit a linear no-threshold model and are still consistent with the notion of a threshold dose for neoplastic transformation in vitro by low LET radiation.

Dysbaric osteonecrosis by X-ray and CT scan in Chinese divers.

OBJECTIVE: To compare the results of X-ray and CT scan for dysbaric osteonecrosis in Chinese divers. METHODS: Both shoulders, hips and knees of 66 asymptomatic divers with diving duration of more than one year were examined by X-ray and CT scan. RESULTS: The most frequent locations of dysbaric osteonecrosis were the upper femurs, followed by the upper humerus, lower femurs and upper tibias, and the most frequent radiographic lesions were calcification spots and cystic changes. Of the lesions detected, 38% (27/71) and 42% (95/229) werejuxta-articular of the femoral and humeral heads by X-ray and CT respectively. The detection rates of dysbaric necrosis (juxta- and/or other lesions) of X-ray and CT scan were 42.4% (95% confidence interval: 30.5%-54.3%) and 81.8% (95% CI: 72.4%-91.2%) respectively (p<0.05). If CT scan was used as the gold standard, the sensitivity of X-ray was 100% and the specificity was 31.6%. CONCLUSION: CT scan showed a higher detection rate of dysbaric necrosis than X-ray. We recommend that CT scan be used for early diagnosis of dysbaric osteonecrosis.

Neoplastic transformation in vitro induced by low doses of 232 MeV protons.

The aim was to define the dose--response curve for high-energy proton-induced neoplastic transformation in vitro. The HeLa x skin fibroblast human hybrid cell assay was used to determine the frequency of neoplastic transformation following doses of 232 MeV protons (mean linear energy transfer, LET=0.44 keV microm(-1)) in the range 5-600 mGy. Proton irradiations were carried out at the Loma Linda University Proton Treatment Facility, CA, USA. The data indicate no evidence for induction of transformation below a dose of 100 mGy. At doses of 5 and 50 mGy, there is evidence for a possible suppression of transformation frequencies below that for spontaneous transformation. The shape of the dose--response curve for high-energy proton-induced transformation of the human hybrid cell line CGL1 does not follow a linear no-threshold model and shows evidence for a threshold as well as for possible suppression of transformation at doses <100 mGy, similar to that seen for other low-LET radiations.

Low doses of diagnostic energy X-rays protect against neoplastic transformation in vitro.

PURPOSE: To investigate the effect of low doses of 60 kVp X-rays on in vitro transformation frequency. MATERIALS AND METHODS: HeLa x skin fibroblast human hybrid cells were used to assay transformation from the non-tumorigenic to the tumorigenic phenotype. Subconfluent cultures of cells were exposed to a range of doses of 60 kVp X-rays and seeded for assay of transformation after 24 h post-irradiation holding. Experiments were repeated at least three times and the data pooled for analysis. Transformation frequencies were compared with those of sham-irradiated controls. RESULTS: At doses < 1 cGy, the observed transformation frequencies were significantly less than those seen in unirradiated cells. CONCLUSION: Low doses (< 1 cGy) of 60 kVp X-rays protect HeLa x skin fibroblast human hybrid cells against neoplastic transformation in vitro.

Lymphocyte DNA damage in cigarette factory workers measured by the Comet assay.

To investigate whether there were separate and combined effects of occupational exposure to tobacco dust and smoking on lymphocyte DNA damage, 148 workers from a cigarette manufacturing factory (107 occupationally exposed to tobacco dust from the production department and 41 unexposed controls who were managerial workers) were included in the study. The Tail Moment (TM) of Comet assay was used to measure DNA damage. The two groups had similar mean age, mean duration of work and smoking prevalence. The exposed workers had a larger TM than that of the controls (mean+/-S.D.: 43.43+/-13. 77 vs. 38.89+/-8.98, p<0.05). Smokers had significantly larger TM than non-smokers (47.25+/-14.02 vs. 38.90+/-10.75, p<0.001). Analysis of variance after adjustment for age and gender showed that occupational exposure and smoking had a significant and independent effect on Tail Moment (p=0.025 and p=0.002, respectively) and there was a significant positive two way interaction between the two factors (p=0.019). Age and gender had no significant effect on TM. The present study suggests that smoking and tobacco dust exposure can induce lymphocyte DNA damage and there is a synergistic effect of tobacco dust exposure and smoking on DNA damage.

Characterization of N-ethyl-N-nitrosourea-induced malignant and benign breast tumors in rats by using three MR contrast agents.

A carcinogen (N-ethyl-N-nitrosourea)-induced animal tumor model was established to grow malignant and benign breast tumors. In each tumor the pharmacokinetic characteristics were measured by using three contrast agents, gadolinium-diethylene-triamine-pentaacetic acid (Gd-DTPA; <1 kD), Gadomer-17 (35 kD), and albumin-Gd-DTPA (70-90 kD). Infiltrating ductal carcinomas (IDC) with low, medium, and high Scarf-Bloom-Richardson grades and fibroadenomas (FA) were analyzed. We found that Gd-DTPA could differentiate between FA and malignant tumors, but not between malignant tumors of low and high grades. In contrast, the intermediate size agent Gadomer-17 could differentiate between high-grade and low-grade IDC, but not between low-grade IDC and FA due to their similar enhancement patterns (despite their different origins). The largest agent, albumin-Gd-DTPA, was capable of differentiating both, but the low contrast-to-noise ratio was its major technical concern. The results in this breast tumor model suggest that macromolecular agents provide useful information for differential diagnosis among IDCs of various grades, but they do not provide superior information than Gd-DTPA for differential diagnosis between IDC and FA.