[Current situation of screening, prevention and treatment of bleeding esophageal varices in cirrhotic portal hypertension in Tibet region: a multicenter study].

Objective: To investigate and analyze the current situation, screening, clinical characteristics, prevention and treatment of bleeding esophageal varices in cirrhotic patients with portal hypertension in Tibet region. Methods: Clinical data of cirrhotic patients with portal hypertension through March 2017 to February 2020 from Tibet region were collected and analyzed retrospectively. Results: 511 cases with liver cirrhosis were included in the study, of which 185 cases (36.20%) had compensated cirrhosis and 326 cases (63.80%) had decompensated cirrhosis. Further analysis of the etiological data of liver cirrhosis showed that 306 cases (59.88%) were of chronic hepatitis B, 113 cases (22.11%) of alcoholic liver disease, and 68 cases (13.31%) of chronic hepatitis B combined with alcoholic liver disease. Among patients with compensated liver cirrhosis, 48 cases (25.95%) underwent endoscopic examination of which 33 diagnosed as high-risk variceal bleeding. However, none of these 33 cases had received non-selective ß-blocker therapy, and only four patients had received endoscopic variceal banding therapy. Among patients with decompensated liver cirrhosis, 83 cases (25.46%) had a history of upper gastrointestinal bleeding, 297 cases (91.10%) had ascites, 23 cases (7.05%) had hepatic encephalopathy, and 3 cases (0.92%) had hepatorenal syndrome. Among the patients with a history of upper gastrointestinal bleeding, 42 cases (50.60%) had received secondary preventive treatment for bleeding esophageal varices, including 39 cases of endoscopic treatment, 1 case of endoscopic combined drug treatment, 3 cases of interventional treatment, and 2 cases of surgical treatment. Conclusion: Chronic hepatitis B and alcoholic liver diseases are the main causes of liver cirrhosis in Tibet region. Moreover, this region lacks screening, prevention and treatment for bleeding esophageal varices in cirrhotic patients with portal hypertension. Therefore, it is necessary to increase the screening of high-risk groups to prevent and improve the first-time bleeding, and promote multidisciplinary team to prevent and treat re-bleeding.

[Intervention effect assessment of response to heatwave in communities of four cities, China].

Objective: To evaluate the intervention effects of response to heatwave in communities of four cities, China. Methods: Baseline survey on heatwave and climate change related knowledge, attitude and practice (KAP) was conducted in the pilot communities in Harbin, Nanjing, Shenzhen and Chongqing, using face-to-face questionnaire interview in November, 2011 to November, 2013. Finally, 1 604 residents were interviewed. Intervention measures were implemented in summers of 2013 and 2014, including delivering early warning information of heatwave health risk and launching health education and promotion. The second survey was conducted in same communities using the same questionnaire and sampling method as baseline survey in November, 2014, and 1 640 residents were interviewed. The Chi-square test was used to compare the demographic characteristics and KAP of community residents between before and after intervention, and the factors that affected the intervention effect were selected by logistic multiple stepwise regression model. Results: The age of the residents interviewed before and after intervention was (46.4 ± 15.5) years and (45.0 ± 15.9) years, respectively. Overall, the residents' awareness rates of heatwave before and after intervention were 70.5% (1 131/1 604) and 82.9% (1 359/1 640) (χ2=69.40, P<0.001). The rate of residents who had wished to receive early warning information increased 6.3% (χ2=41.11, P<0.001), which reached 94.6% (1 551/1 604) after intervention from 88.3% (1 416/1 604) in baseline survey. Both heatwave health risk early warning and health education had big impacts to residents. There were 92.7% (1 105 residents) among the 1 192 residents who had received the early warning information arrange work and rest time according to the early warning information and 93.0% (1 231 residents) among the 1 323 residents who knew about health education activities being conducted in community thought that the community health education activities had made active role in protecting health from heatwaves. After a series of intervention, male had a effect on attitude about hot wave than female in Nanjing and Chongqing, OR (95%CI) were 1.48(1.02-2.16) and 1.45 (1.18-2.05) , respectively; compared with subjects below primary school education, people with college degree or above had higer KAP in all cities (ORs range from 1.18 to 2.05), P<0.05; regular physical exercise (ORs range from 1.39 to 2.70) also had profound impacts on KAP in all cities (P<0.05). Conclusion: s Early warning and health education were effective measures to enhance residents' response capacity to climate change.

Classification of hypothalamic hamartoma and prognostic factors for surgical outcome.

OBJECTIVES: The main aims of this study were to classify patients with hypothalamic hamartoma (HH) based on neuroimaging features and describe the clinical manifestations of HH. MATERIALS AND METHODS: A retrospective review of 214 consecutive patients with HH treated in Beijing Tiantan Hospital was performed. RESULTS: HH were diagnosed and divided into Types I-IV based on MRI. Types I and II were defined as the HH attached to the floor of the third ventricle with narrow (Type I) or broad (Type II) interfaces. Type III ('straddling') was defined by the HH extending into the third ventricle and interpeduncular cistern. Type IV was defined as the HH located totally within the third ventricle. The percent distribution of patients was 35.9% Type I, 12.1% Type II, 40.7% Type III, and 11.2% Type IV. The percentage of patients with precocious puberty was highest in Type I (81.8%). The percentage of patients with gelastic seizures was highest in Type IV (91.7%). After surgery, 20% (1/5) of patients with Type II HH, 48.8% (20/42) with Type III, and 91.7% (11/12) with Type IV were free of epileptic seizures. Significant prognostic factors for surgical outcome were HH size, surgical approach, and resection level. CONCLUSIONS: The clinical manifestations of HH are correlated with the topology of the HH in relation to the hypothalamus. Our results suggest that patients with Type IV HH have the best outcome from surgery and neurosurgeons should be cautious about performing surgery on patients with Type II and Type III HH.

Vasoactive intestinal polypeptide suppresses proliferation of human cord blood-derived hematopoietic progenitor cells by increasing TNF-α and TGF-ß production in the liver.

The physiology of hepatic hematopoiesis is largely unknown, although studies have indicated that vasoactive intestinal polypeptide (VIP) is involved in this disease. To validate this hypothesis, we assessed the effects of VIP on human cord blood CD34+ cells. We also measured VIP levels and the capacity of vasoactive intestinal polypeptide receptor (VIPR) to bind to VIP in the rat liver during different developmental phases. VIP inhibited the proliferation of cord blood-derived CD34(+) cells from concentrations of 10-7-10-12 M. The highest suppression was achieved with 10-8 M VIP at day 10. Intracellular levels of tumor necrosis factor (TNF)-α and transforming growth factor (TGF)-ß1 in CD34(+) cells treated with VIP were increased by 50.70 and 43.46%, respectively. Variations in VIP levels in the rat fetal liver generally increased rapidly with the stage of fetal development. In addition, the affinity of VIPR for VIP increased from relatively low levels in the rat fetal liver and peaked at birth, after which it gradually decreased. VIP had a suppressive effect on the proliferation of human cord blood-derived CD34(+) cells, partially by increasing the production of TNF-α and TGF-ß. Low VIP levels in the fetal liver and gradually increasing levels after birth may in part be responsible for suppressing hematopoietic stem cell and progenitor proliferation in the liver.

Bifidobacterium as an oral delivery carrier of oxyntomodulin for obesity therapy: inhibitory effects on food intake and body weight in overweight mice.

INTRODUCTION: Oxyntomodulin (OXM) is a gut hormone released from intestinal L cell. Synthetic OXM and its analog reduce food intake and body weight in both rodents and human beings by being administered intravenously. However, people find intravenous administration difficult because of its side effects and inconvenience. The aim of this study is to develop a novel oral delivery system for OXM and its analog using genetically engineered Bifidobacterium as the carrier. METHODS: An OXM gene expression vector pBBADs-OXM for the Bifidobacterium genus was constructed. Human OXM sequence was fused with extracellular exo-xylanase (XynF) signal peptide (Xs) from Bifidobacterium longum under the control of the pBAD promoter. B. longum NCC2705 was transformed with the recombinant plasmid pBBADs-OXM by electroporation, and the transformed B. longum was selected using MRS plates containing 60 microg ml(-1) ampicillin. The OXM expression in vitro was identified by western blot and enzyme-linked immunosorbent assay (ELISA) assay after L-arabinose induction. Overweight BALB/c mice were treated with B. longum transformed with OXM after 0.2% L-arabinose induction every day for 4 weeks to investigate the effects of OXM-transformed B. longum on food intake and body weight by oral administration. The B. longum transformed with the green fluorescent protein (GFP) gene was used as negative control; orlistat, a gastrointestinal lipase inhibitor, was used as positive control; Normal saline (NS, 0.9% saline) was used as blank control. The food intakes of each group were measured every day, and body weights were measured once a week. Normal BALB/c (2 months old) mice were treated with OXM-transformed B. longum after induction by intragastric administration every day for 6 days to reveal the mechanism of transformed B. longum, with OXM exerting its biological function by oral administration. Plasma OXM, plasma ghrelin and the OXM of intestinal contents were detected by the ELISA method. Plasma glucose and triglyceride levels were analyzed using the Automatic Biochemistry Analyzer. RESULTS: Transformed B. longum with OXM was selected and identified without biological and morphological alteration. An approximately 4-5 kDa OXM peptide was detected in both the supernatant and the cell pellet of transformed B. longum after L-arabinose induction in vitro. The food intake, body weight and blood triglyceride level of overweight mice treated with OXM-transformed B. longum were all significantly reduced compared with that of the GFP negative control group and NS control group (P<0.01). Interestingly, the plasma triglyceride level of the GFP group was significantly decreased compared with that of the NS control group (P<0.01). The OXM level in the intestinal contents of the OXM group was significantly increased compared with that of the GFP negative control group and the NS group (P<0.05). The plasma ghrelin level of the OXM group was significantly decreased compared with that of the GFP and NS groups (P<0.01). Unexpectedly, the ghrelin level of the GFP group was significantly increased compared with that of the NS control group (P<0.01). CONCLUSION: A novel oral delivery system of Bifidobacterium for human OXM has been successfully established. The expression of recombinant OXM can be detected in the supernatant and cell pellet of transformed B. longum. OXM-transformed B. longum reduces food intake, body weight and plasma lipid level in overweight mice by oral administration.

[Influence of extreme weather on years of life lost due to diabetes death in Chongqing and Harbin, China].

Objective: To understand the associations between extremely low and high air temperature and the years of life lost (YLL) due to diabetes deaths in Chongqing and Harbin with different climatic characteristics in China. Methods: A double threshold B-spline distributed lag non-linear model (DLNM) was used to investigate the lag and cumulative effects of extremely low and high air temperature on YLL due to diabetes for lag 0-30 days by using the urban meteorological and diabetes mortality data of Chongqing (2011-2013) and Harbin (2008-2010). The effects were expressed as relative risk (RR). Results: In Chongqing, the cold effects on YLL due to diabetes were delayed by four days and lasted for three days (lag4-6) with the highest RR of 1.304 (95%CI:1.033-1.647) at lag5. The hot effects were delayed by one day (lag1) with RR of 1.321 (95%CI:1.061-1.646). In Harbin, the extreme cold effects on YLL were delayed by four days and lasted for seven days (lag4-10) with the highest RR of 1.309 (95%CI: 1.088-1.575) at lag6. The hot effects were delayed by one day and lasted for four days (lag1-4) with the highest RR of 1.460 (95%CI:1.114-1.915) at lag2. The unit risk for cold and hot effects was 43.7% (P=0.005 5) and 18.0% (P=0.000 2) in Chongqing and 15.0% (P=0.000 8) and 29.5% (P=0.001 2) in Harbin, respectively. Conclusions: Both extremely low air temperature and extremely high air temperature might increase the years of life lost due to diabetes in cities with different climate characteristics. Health education about diabetes prevention should provide information about the effects of extreme weather events.

Retrovirus-mediated tk gene therapy of implanted human breast cancer in nude mice under the regulation of Tet-On.

Tight regulation of the therapeutic gene expression is critical in gene therapy. In this report, a doxycycline (Dox)-regulated retrovirus-mediated gene expression system was used to study the effects of suicide gene therapy on human breast cancer cell line MCF-7 and the nude mice model of implanted human breast cancer. To render the expression of suicide gene under control, we used two pseudoviruses simultaneously, RevTRE/HSVtk and RevTet-On, to infect MCF-7 cells or xenografts of nude mice. When infected by the pseudoviruses and followed by Dox and Ganciclovir (GCV) treatment, MCF-7 cells were arrested at S phase and the growth was suppressed. We then evaluated the antitumor efficiency of this system in vivo through studying the mice bearing human breast cancer xenografts. Compared with control groups, the HSVtk mRNA level increased significantly in tumor tissues, mass of the tumors shrank remarkably, and tumor necrosis features occurred after treatment with Dox and GCV. These data suggest that suicide gene therapy using the Dox-induced Tet-On-controlled HSVtk gene expression system is a feasible method to treat human breast cancer.

Attenuation of delta opioid receptor-mediated signaling by kainic acid in neural cells: involvement of protein kinase C and intracellular Ca2+.

The potential modulation of opioid receptor signaling by kainic acid (KA) has been investigated in neuroblastoma x glioma NG 108-15 hybrid cells and neuroblastoma SK-N-SH cells. Acute incubation of KA significantly attenuated delta opioid receptor (DOR) signaling induced by the DOR agonist [D-Pen2, D-Pen5]-enkephalin (DPDPE), as measured by activation of G proteins and inhibition of cAMP accumulation. The attenuation by KA was time- and dose-dependent and could be blocked by antagonists of kainate/AMPA receptors, suggesting possible mediation through kainate/AMPA receptors. KA attenuation of DPDPE-stimulated G protein activation was reversed by inhibitors of protein kinase C or by removal of both extracellular Ca2+ and intracellular Ca2+. In contrast, NMDA attenuation of DPDPE-stimulated G protein activation was independent of intracellular Ca2+, indicating that different mechanism(s) may underlie the modulation effect of KA and NMDA. This notion was further supported by the results that KA did not alter nociceptin/orphanin FQ-stimulated G protein activation in NG 108-15 cells but NMDA did. In addition, pretreatment of NG 108-15 cells with antagonists of kainate/AMPA receptors blocked the acute desensitization of DOR signaling. These data provide evidence that KA may be involved in the modulation of opioid receptor signal transduction.

Saikosaponin derivatives from Bupleurum wenchuanense.

From the roots of Bupleurum wenchuanense 14 derivatives of saikosaponin were isolated and identified as 2"-O-beta-D-xylopyranosylsaikosaponin b2, 3",6"-O O-diacetylsaikosaponin b2, 2"-O-beta-D-glucopyranosylsaikosaponin b2, saikosaponin b2, 6"-O-acetylsaikosaponin b2, saikosaponin d, 2"-O-acetylsaikosaponin d, 3"-O-acetylsaikosaponin d,6"-O-acetylsaikosaponin d, 16-epichikusaikoside, prosaikogenin G, saikosaponin a,2"-O-acetylsaikosaponin a and 3"-O-acetylsaikosaponin a. The first two compounds are new derivatives of saikosaponin and this is the first isolation of prosaikogenin G from a plant. Their complete 1H and 13C NMR assignments were made by using a combination of 2D NMR techniques (DQF-COSY, HOHAHA, ROESY, HETCOR, HMQC and HMBC). Some of the compounds showed cytotoxic activity against the P-388 cell line.

Further polyoxypregnanes from Marsdenia tenacissima.

Two new polyoxypregnanes, designated marstenacigenins A and B, along with a known compound, dresgenin, were isolated from the mild acid hydrolysate of the ethanol extract of the stems of Marsdenia tenacissima. Their structures were deduced by a combination of 1D and 2D NMR spectroscopic techniques as 12 beta-cinnamoyl-dihydrosarcostin and 12 beta,20-dibenzoyldihydrosarcostin, respectively.

Food intake and selection pattern of rats treated with dexfenfluramine, fluoxetine and RU 24969.

The effects of two indirect (dexfenfluramine and fluoxetine) and one direct (RU 24969) serotonergic agonists on diet selection over a 12-hr period were examined. Rats were habituated to eat, during the dark period, from two isoenergetic diets that differed in carbohydrate and protein content. Drugs were injected intraperitoneally at 1845 hr, 15 min prior to food access. The drugs exerted their effects mainly during the first hour of feeding (1900-2000 hr). At this time, a selective suppression in intake of the high carbohydrate-low protein diet was the most prominent characteristic of all three serotonergic agonists. This macronutrient specific effect was particularly strong at low dosages (dexfenfluramine, fluoxetine and RU 24969: 0.5, 2.0 and 1.0 mg/kg, respectively). With time, as the effect of drugs wore off, diet selection pattern became more variable. The fact that both indirect 5-HT agonists and a direct selective 5-HT receptor agonist share a specific behavioral effect provides additional support for the role of serotonin in the control of macronutrient specific appetites.

Selective increase in carbohydrate intake by rats treated with 8-hydroxy-2-(di-n-propylamino)-tetraline or buspirone.

Both 8-hydroxy-2-(di-n-propylamino)-tetraline (8-OH-DPAT) and buspirone (BUSP) were found to induce food intake in free-feeding, self-selecting young rats. The hyperphagia was macronutrient specific. In rats given simultaneous access to two diets which differed in carbohydrate and protein content, 8-OH-DPAT and BUSP selectively increased intake from the diet with high carbohydrate content during a two hour test. This specific behavioral effect is dose-dependent and is opposite to that induced by serotonin releasers or reuptake inhibitors. In a separate experiment, the selective decrease in carbohydrate intake after fluoxetine (FLX) was blocked by 8-OH-DPAT co-administration. These results further support a role for the serotonergic system in the control of feeding and macronutrient specific appetites.

Effects of repeated administration of serotonergic agonists on diet selection and body weight in rats.

Food intake, diet selection and body weight gain were examined in three separate experiments in which rats received saline or one of three serotonergic agonists, dexfenfluramine, RU 24969 and fluoxetine. In all experiments, food was available only in the dark period during which time rats were given simultaneous access to two isoenergetic diets which differed in their protein and carbohydrate content. After habituation to this feeding paradigm and intraperitoneal injections, rats were assigned to control or drug group. Saline or a serotonergic agonist was given to the same rat once daily, 15 min prior to feeding, for six consecutive days. All three agonists (1.5 mg/kg for dexfenfluramine and RU 24969; 3 mg/kg for fluoxetine) caused immediate (first two h of feeding) hypophagia which was accounted for by the selective suppression in intake of the high-carbohydrate-low-protein diet. This selective shift in diet choice was sustained upon repeated exposure. Although the effects of these agonists on daily (12-h) feeding was less pronounced, appetite suppression was due entirely to reduced intake of the high-carbohydrate-low-protein diet. Of the three agonists tested, partial tolerance was observed only after dexfenfluramine. Nevertheless, all three agonists caused comparable declines in weight gain. These results suggest that repeated administration of serotonergic agonists has sustained impacts on food intake, diet choice and weight gain.

Mg(2+)-deprivation enhances and Mg(2+)-supplementation diminishes the embryotoxic and teratogenic effects of Ni2+, Co2+, Zn2+, and Cd2+ for frog embryos in the FETAX assay.

The influence of Mg2+ on the embryotoxicity and teratogenicity of Ni2+, Co2+, Zn2+, and Cd2+ for Xenopus embryos was studied by an adaptation of the FETAX protocol. In seven assays, 25 groups of embryos were grown from 5 to 101 hours post-fertilization in FETAX media that contained five graded MgCl2 concentrations (0, 6.2, 62, 620, or 6,200 mumol per L), with or without added NiCl2 (56 mumol per L), CoCl2 (1,800 mumol per L), ZnCl2 (300 mumol per L), or CdCl2 (18 mumol per L). In FETAX assays performed with the standard Mg2+ concentration (620 mumol per L), the incidence of malformations in control embryos averaged 5.4 (SD +/- 1.3) percent; the incidence of malformations in the controls was increased at low Mg2+ concentrations (32 +/- 7 percent at 62 mumol per L; 100 percent at greater than or equal to 6.2 mumol per L). The specified additions of Ni2+, Co2+, Zn2+, or Cd2+ caused death in < 10 under standard conditions (620 mumol Mg2+ per L). Mg(2+)-deprivation greatly enhanced and Mg(2+)-supplementation significantly reduced the incidence and severity of the teratogenic and embryotoxic effects of Ni2+, Co2+, Zn2+, and Cd2+ (p < 0.0001 by analysis of variance [ANOVA]). To explain these findings, the authors speculate that Mg2+ competes with the other divalent metal ions for a carrier mechanism involved in metal absorption or cellular uptake, or for binding to critical molecular targets.

Embryotoxicity and teratogenicity of Cu2+ and Zn2+ for Xenopus laevis, assayed by the FETAX procedure.

Cupric chloride (CuCl2) and zinc chloride (ZnCl2) were tested by the FETAX (Frog Embryo Teratogenesis Assay: Xenopus) procedure in the South African frog, Xenopus laevis. The median teratogenic concentrations (EC50) of Cu2+ and Zn2+ were 2.5 and 40 mumol per L. The median embryolethal concentrations (LC50) of Cu2+ and Zn2+ were 22 and 850 mumol per L. The teratogenic indices (TI = LC50/EC50) were 8.8 for Cu2+ and 21 for Zn2+. Both metal ions were shown to be potent teratogens for Xenopus, causing concentration-related increases of eye, gut, facial, notochord, and cardiac anomalies.

Occipital transtentorial approach for removal of pineal region tumors: report of 64 consecutive cases.

A series of 64 patients with pineal region tumors operated on between 1981 and 1985 at the Beijing Neurosurgical Institute is reported. All were approached using an occipital transtentorial technique. A gross total or radical subtotal removal was achieved in 87% with a total mortality and morbidity of less than 10%. The relative advantages of this particular approach to the pineal region are discussed. It is concluded that the transtentorial approach to the pineal region provides excellent visualization and circumvents many of the pitfalls of other approaches to this region.

Up-regulation of Phosphatidylinositol-3 Kinase Signaling in plcg1 Gene Null Fibroblasts.

Phospholipase C-gamma1(PLC-gamma1) and phosphatidylinositol-3 kinase(PI-3K) play crucial role in growth factor-induced cell growth and proliferation. To investigate the complementary mechanism of PLC-gamma1 in cell growth and epidermal growth factor (EGF)-induced mitogenic signaling, PLC-gamma1 deficient mouse embryonic fibroblasts(PLC-gamma1(-/-)) and its wild type(PLC-gamma1(+/+)) were exposed to U73122, a phospholipase C-specific inhibitor, or wortmannin, a PI-3K inhibitor then the clonogenicity, viability, EGF-induced DNA synthesis of the two cell lines were determined by cloning formation, MTT method and (3)H -thymidine incorporation assay. Results showed that either U73122 or wortmannin inhibited PLC-gamma1(-/-) and PLC-gamma1(+/+) cells in terms of EGF-induced DNA synthesis, cloning formation and cell viability, but PLC-gamma1(-/-) cells were more dependent on PI-3K and less dependent on PLC compared with wild types. The PLC-gamma1 signaling pathway of PLC-gamma1(-/-) cells might be complemented by PI-3K pathway, because after EGF stimulation, the tyrosine phospholation of p85alpha PI-3K increased significantly in PLC-gamma1(-/-), but not in PLC-gamma2(-/-), as Western blotting showed that there was neither complementary PLC-gamma2 expression in PLC-gamma1(-/-) cells, nor other PLC isozymes such as PLC-beta and PLC-delta. These results suggest the redundancy of EGF-mediated signaling and the complementary mechanism of PLC-gamma1 pathway.

Intracranial tumors in children. An analysis of 2000 cases.

Two thousand patients aged 15 years and below, who underwent surgical treatment for intracranial tumors in Beijing Tiantan Hospital from 1955 to 1989, were studied. All of the tumors in this series have been verified by operative findings and histological studies. This series accounts for 15.1% of all cases of intracranial tumors treated within the same period. The characteristics of the histological classifications, locations and clinical manifestations of the intracranial tumors in children are presented. Stresses are placed on the importance of making correct diagnoses in the early stage. Misdiagnoses had been made in 1/4 of the cases in this series before they came to our hospital, thus causing much delayed treatment in many of them. Malignant tumors make up a majority of intracranial tumors in children, and so the prognoses of intracranial tumors are poorer in children than in adults. The authors are of the opinion that adequate radiotherapy is needed after surgical intervention for many of the intracranial tumors.

Inhibitory effect of green tea extract on the carcinogenesis induced by asbestos plus benzo(a)pyrene in rat.

In this experiment lung carcinoma was induced by crocidolite plus benzo(a)pyrene in rat. From the cancer models, we observed that the incidence (16.0%) of lung carcinomas was lower, and the survival time (376 days) of the first case of carcinoma and the mean survival time (758 days) of the rats with carcinoma were higher in the group of rats drinking 2% green tea extract for life than in the positive group (without drinking green tea extract). The mortality ratio (0.5047) was smaller in the experimental group than in the positive control group, and the survival curve of the experimental group significantly raised up, in comparison with the positive group.

The carcinogenicity of several species of asbestos produced in China.

Cases of pleural mesothelioma induced by five species of chrysotile and three species of crocidolite from China in rats are compared. The rate of induction in the chrysotile group (43.1%) was slightly lower than that in the crocidolite group (56.7%). The survival time of the first case of mesothelioma in the chrysotile group was 408 days and in the crocidolite group 377 days. The major histological types of mesothelioma induced by chrysotile were epithelial and mixed, but the major type in the crocidolite group was fibrous. The extent of differentiation in all mesotheliomas, mainly intermediate and low, was nearly the same.