[Comparison of quantitative detection of BCR::ABL1 p210 transcript levels: a multicenter study].

Objective: To assess the capability of seven reference medical laboratories to detect BCR::ABL1 p210 transcription levels and to compare the results among those laboratories. Methods: The interlaboratory comparison was carried out in two stages. The samples were prepared by the reference laboratory. The quantitative values of BCR::ABL1 p210 of the comparison samples covered 0.001%-0.01%, 0.01%-0.1%, 0.1%-1%, 1%-10% and>10% in each stage. Real-time quantitative PCR (RT-PCR) and dPCR (digital PCR) were used to examine the samples. The conversion factor (CF) was calculated and validated for each laboratory. Results: In the RT-PCR comparison, one laboratory was failed to detect BCR::ABL1 p210 in fourteen samples at the first stage. The results of the other six laboratories were qualified with the bias <±1.2 folds (-0.133-0.338) and 95% limits of agreement within ±5 folds (upper limit 0.147-0.785, lower limit -0.770--0.109), and the corresponding CF values were calculated and validated. In the dPCR comparison, one laboratory did not report results at the second stage. The results of the other six laboratories were qualified with the bias <±1.2 folds (-0.026-0.267) and 95% limits of agreement within±5 folds (upper limit 0.084-0.991, lower limit -0.669--0.135), and the corresponding CF values were calculated and validated. The samples with BCR::ABL1 p210 quantitative values of 0.01%-0.1%, 0.1%-1%, 1%-10% and >10% could be detected by both RT-PCR and qPCR. When the quantitative value of BCR::ABL1 p210 was 0.001%-0.01%, the detection rate of dPCR was higher than that of RT-PCR (85.56% vs. 68.00%). Conclusions: A good consistency is present among various laboratories. The quantitative value of BCR::ABL1 p210 is comparable among laboratories as shown by the CF value conversion. For quantitative detection of BCR::ABL1 p210 deep molecular reaction, dPCR has a higher positive detection rate and more advantages than RT-PCR. To ensure the accuracy and reproducibility of the BCR::ABL1 p210 test, it is imperative for every laboratory to enhance their daily quality control practices.

[A comparative study between direct mechanical thrombectomy and bridging therapy in patients with atrial fibrillation associated anterior circulation large vessel occlusion stroke].

From January 1, 2015 to December 31, 2021, 94 patients who were diagnosed with atrial fibrillation (AF) associated anterior circulation large vessel occlusion stroke and underwent mechanical thrombectomy in the First Affiliated Hospital of Dalian Medical University were retrospectively collected, including 52 patients in the direct mechanical thrombectomy (dMT) group and 42 patients in the bridging therapy (BT) group. All patients received stent thrombectomy, and the BT group received intravenous thrombolytic therapy with alteplase within 4.5 hours.There were no significant differences in 7 d National Institute of Health Stroke Scale (NIHSS) score[12.0 (5.2, 42.0) vs 10.0 (6.0, 25.8)], incidence of hemorrhage transformation [44.2%(23/52) vs 45.2%(19/42)], symptomatic intracranial hemorrhage[11.5%(6/52) vs 11.9%(5/42)],90 d mortality[34.6% (18/52) vs 38.1% (16/42)]between the two groups(all P>0.05). The rate of 90 d good prognosis in dMT and BT groups was 36.5% (19/52) and 35.7% (15/42), respectively, and the difference was not statistically significant(OR=1.45, 95%CI: 0.39-3.37, P=0.805). The number of stent passes[2(1,3) vs 1(1,2)] and the vessel recanalization time [(81±41)min vs (57±29)min] in the BT subgroup of middle cerebral artery (MCA) occlusion were longer than those in the dMT group (both P<0.05).Therefore, direct thrombectomy has similar efficacy and safety as bridging therapy in the treatment of AF related anterior circulation large vessel occlusive stroke, which is worthy of further research and verification.

[Mutational features of immunoglobulin heavy chain variable region gene in patients with chronic lymphocytic leukemia].

Objective: To investigate the mutational features of the immunoglobulin heavy chain variable region (IgHV) gene in patients with chronic lymphocytic leukemia (CLL) using immunophenotypic and molecular genetic methods. Methods: The laboratory results of 266 CLL patients who underwent IgHV gene examination at Sino-US diagnostics laboratory from February 2020 to February 2021 were analyzed for the IgVH mutational status and presence of specific IgVH fragments. In addition, their immunophenotypic, molecular, chromosomal karyotypic, and FISH profiles were investigated and correlated with the IgVH mutational status. Results: Among 266 patients, 172 were male and 94 were female, with a media age of 67 years (20-82 years).There were more patients with mutated IgHV (m-IgHV) than unmutated IgHV (un-IgHV) (69.2%∶30.8%). There was association of VH family and the presence of gene fragments: the overall incidence of VH families including VH3 family (142/266, 53.4%), VH4 family (75/266, 28.2%), and VH1 family (34/266, 12.8%) was about 95%, among which the proportion of VH4-34 (26/266, 9.8%), VH3-23 (25/266, 9.4%), VH3-7 (24/266, 9.0%), and VH4-39 (16/266, 6.0%) was about 35%. VH3-20 and VH3-49 only occurred in un-IgHV (P<0.05). In addition, the expression rates of CD38 (26.3% vs. 3.0%), CD79b (71.1%∶45.5%) and 11q deletion (25.5%∶5.3%) were higher in un-IgHV, and single trisomy 12 (37.9%∶5.6%) were more commonly found in m-IgHV (P<0.05). MYD88 was one of the major mutation genes in m-IgHV, while ATM had the highest mutation rate in un-IgHV. Conclusion: CLL patients have differential expression in terms of IgHV gene mutations, correlating to their immunophenotype and genetics characteristics.

[Characteristics of fusion gene expression in acute lymphoblastic leukemia].

Objective: To analyze the genetic landscape of 52 fusion genes in patients with de novo acute lymphoblastic leukemia (ALL) and to investigate the characteristics of other laboratory results. Methods: The fusion gene expression was retrospectively analyzed in the 1 994 patients with de novo ALL diagnosed from September 2016 to December 2020. In addition, their mutational, immunophenotypical and karyotypical profiles were investigated. Results: In the 1 994 patients with ALL, the median age was 12 years (from 15 days to 89 years). In the panel of targeted genes, 15 different types of fusion genes were detected in 884 patients (44.33%) and demonstrated a Power law distribution. The frequency of detectable fusion genes in B-cell ALL was significantly higher than that in T-cell ALL (48.48% vs 18.71%), and fusion genes were almost exclusively expressed in B-cell ALL or T-cell ALL. The number of fusion genes showed peaks at<1 year, 3-5 years and 35-44 years, respectively. More fusion genes were identified in children than in adults. MLL-FG was most frequently seen in infants and TEL-AML1 was most commonly seen in children, while BCR-ABL1 was dominant in adults. The majority of fusion gene mutations involved signaling pathway and the most frequent mutations were observed in NRAS and KRAS genes. The expression of early-stage B-cell antigens varied in B-cell ALL patients. The complex karyotypes were more common in BCR-ABL1 positive patients than others. Conclusion: The distribution of fusion genes in ALL patients differs by ages and cell lineages. It also corresponds to various gene mutations, immunophenotypes, and karyotypes.

[Efficacy of intravenous thrombolysis in acute ischemic stroke with hyperdense middle cerebral artery sign].

Objective: To observe the efficacy and safety of recombinant tissue-type plasminogen activator (rtPA) intravenous thrombolysis (IVT) in the treatment of acute cerebral infarction with hyperdense middle cerebral artery sign (HMCAS). Methods: Acute cerebral infarction patients with HMCAS from July 2010 to November 2015 at the First Affiliated Hospital of Dalian Medical University were collected.These patients were divided into two groups depending on whether they received IVT or not.The Nation Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS) were used to evaluate early and long-time therapeutic effects.Efficacy and safety were compared between the two groups. Results: A total of 93 patients were eligible for the analysis, with 45 cases in IVT group and 48 cases in non-IVT group.As time went by, NIHSS score in IVT group showed significant downward trend than the non-IVT group.The rate of patients with good outcome in IVT group was higher than that in non-IVT group (P<0.05). The rate of hemorrhage transformation (HT) in IVT group and non-IVT group was 35.6% (16/45) and 10.4% (11/48), respectively, and the difference was statistically significant (P<0.05). While no statistically significant difference was found about the rate of symptomatic intracranial hemorrhage (sICH) (8.9% vs 2.1%, P>0.05) and mortality (33.3% vs 27.1%, P>0.05) between these two groups.Logistic regression analysis identified relativity between IVT treatment and good outcome (P<0.05), hemorrhage transformation (P<0.05), rather than mortality (P>0.05). Conclusions: Intravenous thrombolysis with rt-PA is an effective and safe treatment for most acute ischemic stroke patients with HMCAS and can promote early neurologic improvement and significantly improve long-term functional prognosis.Although Ⅳ thrombolysis can increase the risk of overall HT, it does not add risk in sICH and mortality.

[Effect of intravenous thrombolysis with recombinant tissue type plasminogen activator (rt-PA) in different time windows on acute cerebral infarction patients with atrial fibrillation].

OBJECTIVES: To observe the intravenous thrombolysis effect of rt-PA in different time windows of acute cerebral infarction with atrial fibrillation(AF). METHODS: Acute cerebral infarction patients who accepted the intravenous thrombolysis treatment with AF from January 2012 to December 2015 were included.According to the time from onset to intravenous thrombolysis, patients were divided into two groups: thrombolysis within 3 h and thrombolysis between 3-4.5 h. The Nation Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS) were used to evaluate early and long-time therapeutic effects. The incidence of hemorrhagic infarction(HI), parenchymal hemorrhage(PH) and symptomatic intracranial hemorrhage(sICH) after thrombolysis within 24 hours were observed in the two groups. RESULTS: A total of 103 patients were included in the study, with 48 cases in thrombolysis within 3 h group and 55 cases in thrombolysis between 3-4.5 h group. After thrombolysis treatment, the 24-hour and 7-day NIHSS score of the two groups were significant lower than before treatment, and the difference was statistically significant(P<0.05). Compared between groups, 24-hour clinical efficacy of thrombolysis within 3 h group was better than that of thrombolysis between 3-4.5 h group, and the difference was statistically significant(P<0.05). There were no statistically significant differences between these two groups about 7-day and 90-day prognosis(P<0.05). The rate of PH in thrombolysis within 3 h group and thrombolysis between 3-4.5 h group is 6.3%(3/48) and 21.8%(12/55) individually, and the difference was statistically significant(P<0.05). While no statistically significant differences was found about the rate of HI(18.8% vs 32.7%, P>0.05) and sICH(8.3% vs 14.5%, P>0.05) between these two groups. CONCLUSIONS: For patients of acute cerebral infarction with AF, intravenous thrombolytic therapy by rt-PA within 3 h may contribute to a greatly improvement in a short time. Thrombolysis between 3-4.5 h increase the incidence of PH, but do not increase the incidence of sICH. There are no statistically significant differences between these two groups about 90-day favorable prognosis, indicating that thrombolysis between 3-4.5 h is safe and effective for acute cerebral infarction patients with AF.

[Characterization of mutational pattern in patients with Ph negative myeloproliferative neoplasms].

OBJECTIVE: To characterize the molecular profile in patients with Ph negative myeloproliferative neoplasms (MPN) by exploring 49 gene mutations. METHODS: Targeted gene sequencing were performed to analyze 49 MPN-associated genes in 51 patients with Ph negative MPN, of which CARL (exon 9), NPM1 (exon 12) and CEBPA (TAD, BZIP domains) were investigated by using Sanger sequencing simultaneously, while FLT3-ITD was assessed by PCR method. RESULTS: Mutations were detected in 73.5% (36/49) of genes, and the mutational rates of JAK2-V617F, CALR (exon 9) and MPL were 60.8%(31/51), 7.8%(4/51) and 7.8%(4/51) respectively, whereas the mutational rates of ASXL1, SETBP1, and SF3B1 were around 10%. In addition, 96.1% (49/51) of patients harbored at least one mutation, and more than half of the patients (52.9%, 27/51) possessed 3 or 4 gene mutations. The amount of gene mutations was significantly higher in patients with JAK2-V617F mutation than those without JAK2-V617F or CALR (exon 9) mutation (P<0.05). The last finding was that there was no statistically significant difference in the amount of mutations among four MPN subtypes (PV, ET, PMF, and MPN-U). CONCLUSION: Most patients with Ph negative MPN possesses three or more gene mutations, with various mutational profiles.

Increased subsequent risk of acute coronary syndrome for patients with dermatomyositis/polymyositis: a nationwide population-based retrospective cohort study.

OBJECTIVES: The aim of this study was to explore the possible association between dermatomyositis/polymyositis (DM/PM) and subsequent acute coronary syndrome (ACS) risk. METHOD: We used data from the National Health Insurance (NHI) system of Taiwan to address the research topic. The exposure cohort contained 2029 patients with new diagnoses of DM/PM. Each patient was randomly frequency-matched according to sex and age with four participants from the general population who did not have a history of ACS at the index date (control group). Cox proportional hazard regression analyses were conducted to estimate the relationship between DM/PM and subsequent ACS risk. RESULTS: Among patients with DM/PM, the overall risk for developing subsequent ACS was significantly higher than that of the control group [adjusted hazard ratio (aHR) 1.98, 95% confidence interval (CI) 1.17-3.35]. Further analysis indicated a higher risk in patients who were male, older, or diagnosed with comorbidities. CONCLUSIONS: The findings from this population-based retrospective cohort study suggest that DM/PM is associated with an increased subsequent ACS risk.

Anti-tuberculosis treatments and risk of hepatocellular carcinoma in tuberculosis patients with liver cirrhosis: a population-based case-control study.

The objective of this study was to evaluate the association between the use of anti-tuberculosis (anti-TB) agents, isoniazid (INH), rifampicin (RIF), and their combination (INH + RIF), and the risk of hepatocellular carcinoma (HCC) in cirrhotic patients. This population-based case-control study was conducted using a research database of Taiwan's National Health Insurance program. Cirrhotic patients first diagnosed with HCC between 1996 and 2011 (n = 50,351), among whom 4,738 were anti-TB medication users, were evaluated. Cirrhotic patients who did not develop HCC within the same period, frequency-matched according to age, sex, and index year, were evaluated as the control group (n = 47,488). The adjusted odds ratio (OR) of HCC was 1.34 [95 % confidence interval (CI), 1.20-1.50] in INH + RIF users compared with non-INH + RIF users. Long-term (>12 months) use of INH, RIF, and INH + RIF was significantly associated with increased risk of HCC, with an adjusted OR of 3.51 (95 % CI, 2.11-5.84), 4.17 (95 % CI, 2.76-4.31), and 7.17 (95 % CI, 4.08-12.6), respectively, after adjusting for age, sex, and comorbidities. An average dose of INH + RIF >16,050 mg/year was associated with increased risk of HCC in cirrhotic patients, with an adjusted OR of 1.48 (95 % CI, 1.27-1.73). Our results indicate that cirrhotic patients with long-term or high-dose INH and RIF treatment, particularly their combination, are associated with increased risk of HCC development.

Identification of a novel cyprinid herpesvirus 3 genotype detected in koi from the East Asian and South-East Asian Regions.

Cyprinid herpesvirus 3 (CyHV-3) is a highly contagious virus that causes significant morbidity and mortality in common carp Cyprinus carpio L. and considered to be one of the most important pathogens of koi and common carp worldwide. Cyprinid herpesvirus 3 infected consignments imported from East Asian and South-East Asian regions were identified during quarantine period in Singapore, and virus from a 2005 consignment was successfully isolated in koi fin cells. A combination of sequence analyses and duplex PCR were used to characterize 15 CyHV-3 isolates detected in koi consignments between 2005 and 2011. Sequence analyses of the enlarged 9/5, SphI-5 and TK gene regions identified both the Asian 1 (n = 11) and European 4 (n = 4) genotypes. Duplex PCR analysis of two variable marker regions between ORF29 and ORF30 (marker I) as well as ORF133 and its upstream region (marker II) revealed viruses of genotypes J (I++ II+ ), U/I (I-- II- ), an intermediate genotype (I++ II- ) and a novel genotype, I++ II+Δ , which was identified in viruses from seven different consignments. This novel genotype has a 13-bp deletion in marker II, while maintaining the I++ allele of marker I. The I++ II+Δ genotype may have emerged from East Asian and South-East Asian regions in recent years.

Gender difference in protein expression of vascular wall in mice exposed to chronic intermittent hypoxia: a preliminary study.

Obstructive sleep apnea (OSA) is an independent risk factor for cardiovascular diseases such as systemic arterial hypertension, ischemic heart disease, stroke, heart failure, atrial fibrillation, and cardiac sudden death. The pathogenesis of cardiovascular disease in OSA is thought to be induced primarily by chronic intermittent hypoxia (CIH), a specific pattern of change in oxygenation during sleep. However, the underlying mechanisms of CIH-induced vasculature injury and gender differences are not well documented. The iTRAQ Quantitative Proteomic method enables analysis of a number of different proteins among several groups. Thus, we explored gender differences in protein expression in the vascular walls of mice exposed to CIH. C57BL/6J mice of each gender were exposed to CIH with a fractional inspired O2 (FiO2) nadir of 5% or control, with a treatment time of 8 h/day for 28 days. Differential proteins related to CIH-induced vascular injury between genders were identified using iTRAQ proteomic technology. A total of 163 proteins were identified, of which 34 showed significant differences between genders, which may correlate with vascular injury by CIH. Twenty up-regulated proteins and 14 downregulated proteins were observed in female mice compared with male mice. We identified different vascular proteins expressed under CIH between genders, suggesting that these proteins may be biomarkers of vascular injury by CIH.

[Analysis of fusion gene expression in acute myeloid leukemia].

Objective: To analyze the genetic landscape of multiple fusion genes in patients with de novo acute myeloid leukemia (AML) and investigate the characteristics of immunophenotypes and mutations. Methods: The results of multiple fusion genes from 4192 patients with de novo AML were retrospectively analyzed from 2016 to 2020. In addition, the immunophenotypical data and the mutational results from high-through put method were statistically investigated and correlated as well. Results: ①Among the 52 targets, 29 different types of fusion genes were detected in 1948 patients (46.47%) with AML, which demonstrated an "exponential distribution" . ② As the age increased, the number of patients with fusion gene increased first and then decreased gradually. The total incidence rate of fusion genes and MLL rearrangment in children were significantly higher than those in adults (69.18% vs 44.76%, 15.35% vs 8.36%) . ③The mutations involving FLT3 and RAS signaling pathway contributed most in patients with MLL rearrangment. ④No specific immunophenotypic characteristics were found in AML patients with MLL or NUP98 rearrangements. Conclusion: Nearly half of AML patients were accompanied by specific fusion gene expression, the proportions of different fusion genes in pediatric and adults patients were different by multiple PCR. The gene mutations and immunophenotype of these AML patients have certain rules.

Knowledge and Perceptions of Child Protection and Mandatory Reporting: A Survey of Nurses in Hong Kong.

In the absence of a mandatory reporting (MR) structure, it is unclear how nurses perceive or exercise their role in child protection. This study examined knowledge and perceptions of child protection and MR among nurses working in Hong Kong. This cross-sectional web-based survey used the Child Abuse Report Intention Scale to measure nurses' child protection knowledge and attitudes, and their perceived norms, control, and intention to report suspected maltreatment. Nurses also indicated if they support MR and to provide an explanation for their preference. Quantitative data were described and analyzed using bivariate and regression analyses. Open-ended responses were analyzed using directed content analysis. A convenient sample of 91 nurses working in Hong Kong completed the survey. The majority (86%) were female with a mean of 9.5 years of nursing experience; their mean knowledge score was 6.64 out of 13 (range 2-10). Compared with other maltreatment types, sexual abuse was perceived to be most severe and most likely to be reported. Perceived severity and attitudes toward child maltreatment was significantly associated with nurses' intention to report. Over half (58%) supported MR; those against MR expressed concerns about lack of support from management. Although nurses working in Hong Kong still hold polarized views about MR, findings point to the importance of creating a supportive reporting culture, and designing training programs that focus on changing perceptions about child protection in order to improve their tendency to report.

[Mutational analysis of RNA splicing machinery genes SF3B1, U2AF1 and SRSF2 in 118 patients with myelodysplastic syndromes and related diseases].

Objective: To investigate the incidence, molecular features and clinical significance of RNA splicing machinery genes mutation in myelodysplastic syndromes (MDS) and related diseases. Methods: Mutational analysis of splicing factor 3B subunit 1 (SF3B1) (K700E) , U2 small nuclear RNA auxiliary factor 1 (U2AF1) (S34, Q157P) and serine/arginine-rich splicing factor 2 (SRSF2) (P95) in 118, de novo MDS and related diseases were separately performed by using polymerase chain reaction (PCR) followed by sequence analysis. Results: Of 118 MDS patients, 76 males and 42 females, the median age was 53.5 (13-84) years old. 19.49% (23/118) had SF3B1 (K700E) mutation. As compared with those with wild type SF3B1, patients with SF3B1 K700E were of older[58 (32-78) years vs 51 (13-84) years, z=-1.981, P=0.048], lower HGB level[63 (40-95) g/L vs 77 (34-144) g/L, z=-3.192, P=0.001], higher platelet counts[121 (22-888) ×10(9)/L vs 59 (6-1 561) ×10(9)/L, z=-3.305, P=0.001], lower bone marrow blast cell counts[0.007 (0-0.122) vs 0.017 (0-0.268) , z=-2.885, P=0.004], higher ring sideroblasts percent [0 (0-64%) vs 0 (0-58%) , z=-4.664, P<0.001]. Of 105 MDS patients, 21.9% had U2AF1 (S34, Q157P) mutations. Of 107 MDS patients, 8 patients (7.48%) had SRSF2 (P95) mutations. Patients with SRSF2 mutations were older at diagnosis, the median age was 63 (50-84) years old, including 4 cases RAEB-1. The ratio of mutation was 14.29% (4/28) , and three patients transformed to AML. SF3B1 K700E and SRSF2 P95H mutations coexisted in 1 patient, and SF3B1 K700E and U2AF1 S34Y mutations were found concomitantly in 2 patients. Conclusion: Only SF3B1 gene mutation was closely related to ring sideroblasts, it was the key to pathogenesis of MDS.

Enhanced sympathetic outflow and decreased baroreflex sensitivity are associated with intermittent hypoxia-induced systemic hypertension in conscious rats.

Long-term exposure to intermittent hypoxia (IH), such as that occurring in association with sleep apnea, may result in systemic hypertension; however, the time course changes in arterial pressure, autonomic functions, and baroreflex sensitivity are still unclear. We investigated the changes in cardiovascular neural regulations during the development of chronic IH-induced hypertension in rats. Sprague-Dawley rats were exposed to repetitive 1.25-min cycles (30 s of N2+45 s of 21% O2) of IH or room air (RA) for 6 h/day during light phase (10 AM-4 PM) for 30 days. Arterial pressure was measured daily using the telemetry system during RA breathing. The mean arterial pressure (MAP) and interpulse interval (PPI) signals were then used to assess the autonomic functions and spontaneous baroreflex sensitivity by auto- and cross-spectral analysis, respectively. Stable MAP, low-frequency power of MAP (BLF), and low-frequency power (LF)-to-high frequency power (HF) ratio of PPI (LF/HF) were significantly higher in IH-exposed rats, compared with those of RA-exposed rats. Elevation of the MAP, BLF, LF/HF, and minute ventilation started 5 days after IH exposure and lasted until the end of the 30-day observation period. Additionally, IH-exposed rats had significant lower slope of MAP-PPI linear regression (under a successively descending and ascending) and magnitude of MAP-PPI transfer function (at frequency ranges of 0.06-0.6 Hz or 0.6-2.4 Hz) after IH exposure for 17 days. However, RA-exposed rats did not exhibit these changes. The results of this study indicate that chronic IH-induced hypertension is associated with a facilitation of cardiovascular sympathetic outflow and inhibition of baroreflex sensitivity in conscious rats.

Effect of diet high in beef fat on the composition of fecal bile acids during intestinal carcinogenesis in the rat.

Two groups of 20 male Sprague-Dawley rats each were given sc 8 mg azoxymethane/kg body weight and fed a normal diet or one high in beef fat. Control groups were not given azoxymethane. Fat-control animals did not excrete more total bile acids than did the normal-control group but did excrete more deoxycholic acid as the result of increased cholic acid degradation. Azoxymethane itself caused an increase in fecal bile acid concentratation but tended to reduce the level of cholic acid degradation. Fatty acid content in the feces increased in the animals on the fat diet but was not affected by azoxymethane. A fat-diet-dependent increase was apparent in total fecal neutral steroids and a carcinogen-dependent increase in cholesterol degradation. Dietary fat and bile steroids altered by gut microflora were important interrelated factors in the intestinal carcinogenic process of this animal model.