[Short-term outcomes of all-inside endoscopic running locked stitch technique for acute achilles tendon ruptures]

Objective: To evaluate the short-term outcomes of all-inside endoscopic running locked stitch technique for acute Achilles tendon ruptures. Methods: This is a retrospective case series study. Forty cases with acute Achilles tendon rupture were treated with the all-inside endoscopic running locked stitch technique from April 2020 to March 2022. There were 44 males and 4 females, aged (34.8±7.4) years (range: 24 to 50 years). Body mass index was (21.2±2.4)kg/m2 (range: 18 to 26 kg/m2); There were 29 cases (60.4%) on the left side and 19 cases (39.6%) on the right side. Under endoscopic control, the proximal tendon stumps were stitched with the running locked method using a semi-automatic flexible suture passer. The threads of the high-strength suture were grasped through the paratenon sub-space and then fixed into calcaneal insertion with a knotless anchor. MRI of Achilles tendon, surgical time and complications were assessed. Achilles tendon total rupture score (ATRS), Achilles tendon resting angle, and heel rise height scale were utilized to evaluate final clinical outcomes. The differences of bilateral limbs were compared using the paired t test. Results: The follow-up time was (24.1±3.5)months (range:18 to 32 months). Appropriate tendon regeneration was observed on MRI at post-operative 12 months. The median ATRS score (M(IQR)) was 95.0 (4.7) points. Furthermore, there was no significant difference between the injured and contralateral side in the Achilles tendon resting angle ((17.1±2.4)° vs. (17.4±2.6)°, t=1.92,P=0.062) and heel rise height ((14.2±1.7)cm vs. (14.4±1.5)cm, t=1.71,P=0.094). No nerve injuries, infection, deep vein thrombosis and re-ruptures were encountered. Sports activity resumed six months postoperative in 46 patients. One patient had a slight anchor cut-out, due to an addition injury, which was removed after 5 months. Conclusions: All-inside endoscopic running locked stitch technique for acute Achilles tendon ruptures shows promising results. It provides stable connection of the tendon stumps with a low risk of complications.

Secondary ear reconstruction based on the Nagata method after unsatisfactory microtia surgery outcomes

BACKGROUND

Follow-up studies on auricular reconstruction procedures have reported postoperative complications; some of which can only be reversed with revision surgery. This study aims to provide a feasible surgical strategy based on the Nagata method for patients requiring secondary revision and verify mid-term aesthetic outcomes.

METHODS

Secondary auricular reconstructions based on the Nagata method were performed on seven patients seeking secondary revision between 2017 and 2021. Scores of a five-point Likert scale and artificial intelligence ratings based on convolutional nerve networks were used as outcome measures.

RESULTS

Five patients underwent complete two-stage ear reconstruction, and the other two patients underwent the first-stage microtia procedure only. Few complications were observed, except in Case 4; this patient required an additional minor surgery after frame exposure 6 weeks after the first-stage procedure. All revised ears showed clear anatomical structures, and all patients were satisfied with the aesthetic results. Statistical analysis showed a significant increase in postoperative versus preoperative scores by convolutional neural network models (p < 0.05). Cases 5 and 6, which involved projection surgeries only, had decreased artificial intelligence appearance scores postoperatively.

CONCLUSION

After adequate preoperative evaluation, secondary auricle reconstruction based on the Nagata method can achieve reliable aesthetic outcomes with few complications.

CLINICAL TRIAL REGISTRATION INFORMATION

ClinicalTrials.gov ID: NCT05604456.

Stoma-site approach single-port laparoscopic versus conventional multi-port laparoscopic Miles's procedure for low rectal cancer: A prospective, randomized controlled trial

OBJECTIVE

The aim of this study was to compare perioperative outcomes of patients with low rectal cancer after stoma-site approach single-port laparoscopic Miles procedure or conventional multi-port laparoscopic Miles procedure, as well as to evaluate the safety and efficacy of stoma-site approach single-port laparoscopic surgery in low rectal cancer.

METHODS

Between September 2020 and September 2021, 51 low rectal cancer patients scheduled for Miles procedure at the Department of Gastrointestinal Surgery of Affiliated Hospital of North Sichuan Medical College were randomly assigned to the single-port laparoscopic surgery group (SPLS) and the multi-port laparoscopic surgery (MPLS) group. The perioperative outcomes were compared between the two groups.

RESULTS

In this study, 25 patients underwent SPLS and 26 underwent MPLS. All patients completed the study, and there were no perioperative deaths in either group. Observation indicators such as intraoperative bleeding (39 mL vs. 41 mL), number of lymph nodes (20.12 ± 3.29 vs. 21.84 ± 3.74), average hospital stay (7.15 ± 1.52 vs. 7.64 ± 1.66), and time to flatulence (2.5d vs. 2.5d) showed no significant differences between the SPLS and MPLS groups (p > 0.05). However, the operation duration (180 min vs. 118 min) and perioperative complications showed statistically significant differences between the two groups (p < 0.05). In addition, patients in the SPLS group had significantly higher satisfaction scores than those in the MPLS group (p < 0.05).

CONCLUSION

For patients with low rectal cancer requiring Miles surgery, stoma-site approach single-port laparoscopic surgery has comparable safety and efficacy to multi-port laparoscopic surgery.

Total laparoscopic segmental gastrectomy for gastrointestinal stromal tumors: A case report

BACKGROUND

Gastrointestinal stromal tumors are lesions that originate from digestive tract walls. Several laparoscopic techniques, including local resections, wedge resections and partial gastrectomies, have been used successfully. However, there are no reports on laparoscopic segmental gastrectomy for gastrointestinal stromal tumors.

CASE SUMMARY

We present our analysis of 17 patients who were admitted to our hospital from January 2014 to December 2018. All tumors were located in the corpus and antrum of the stomach, close to the lesser curvature of the stomach. The tumors originated from the anterior wall in nine cases and from the posterior wall of the stomach in eight cases. Laparoscopic segmental gastrectomy and end-to-end anastomosis between the proximal and the distal residual stomach were used in all patients. The mean operative time was 112.4 min. The mean length of hospital stay was 4.6 d. Mean operative blood loss was 73.5 mL. There were no leaks, no postoperative bleeding nor need for reintervention. Mean postoperative follow-up was 35.4 mo. The Visick grading index showed fewer gastrointestinal symptoms 3 mo after surgery. Two patients (11.8%) had reflux esophagitis and gastritis.

CONCLUSION

Laparoscopic segmental gastrectomy may be a new function-preserving gastrectomy that is feasible for treatment of gastrointestinal stromal tumors that grow in the middle third of the stomach and on the lesser stomach curvature.

A huge bladder diverticulum in an elderly: A case report

An 81-year-old male patient presented to the department of gastroenterology with increasing lower abdominal pain for 2 years, aggravated with bloody stool for 1 month. Computed tomographic examination revealed a huge cyst (207 × 93 × 208 mm³) in the abdominal cavity, absence of bladder, thickening and strengthening of the rectal wall, and benign prostatic hyperplasia. Colonoscopy showed colon cancer and surgery was planned. Interestingly, after magnetic resonance imaging and cystography, we found colon cancer and a large bladder diverticulum rather than tumor metastasis or others. Severe bacteremia occurred in the elderly chronic obstructive pulmonary disease patient before operation. After careful consideration, we decided to take a large risk and combined urology and gastrointestinal surgery professionals to carry out bladder diverticulectomy, cystostomy, radical resection of rectal carcinoma, and so on. Fortunately, the patient recovered well after the operation. In addition to the common tumor metastasis and cystadenoma, the abdominal mass should also be alert to the rare bladder diverticulum, which eventually leads to diagnostic confusion. Multidisciplinary diagnosis and treatment has become an important treatment for complex diseases.

Endoscopic titanium clip closure of gastric fistula after splenectomy: A case report

This report describes a 52-year-old male patient with blunt abdominal traumatic rupture of the spleen due to injuries sustained in an automobile accident. Following splenectomy, the patient developed a gastric fistula. He underwent a long period of conservative treatment, including antibiotics and total parenteral nutrition, which was ineffective. The fistula could not be closed and titanium clip closure using a gastroscopy was then performed in order to close the fistula. After endoscopic therapy and clipping surgery, the patient’s general condition improved significantly, and he had no post-procedural abdominal complications. On post-clipping day 6, the gastric fistula was completely closed as shown by X-ray examination of the upper digestive tract. The patient was discharged from hospital and no complications were observed during the six-month follow-up period. Our report suggests that titanium clip closure using endoscopy may be the choice of treatment in patients with a gastric fistula.

Genetic polymorphisms of the FATP1 gene and their associations with meat quality traits in Chinese Qinchuan cattle

Fatty acid transport protein 1 (FATP1), an integral membrane protein that facilitates long-chain fatty acid influx, is involved in the genetic network for oleic acid synthesis. The aim of this study was to examine the association of FATP1 polymorphisms with live animal meat quality traits in Chinese Qinchuan cattle. Quantitative real-time PCR analysis demonstrated that FATP1 has a broad tissue distribution in Qinchuan cattle and is highly expressed in longissimus dorsi muscle and back fat. Using direct DNA sequencing of the FATP1 gene in 458 Qinchuan cattle, four single nucleotide polymorphisms (SNPs; g.28265 G>C, g.28381 G>A, g.28470 T>C, and g.28672 G>A) were identified for genotyping within a 671-bp region, including exon 3, intron 3, exon 4, intron 4, and part of exon 5 of the FATP1 gene. Positive effects of genotypes CC (g.28470 T>C locus) and AA (g.28672 G>A locus) on meat quality traits were obtained by association analysis. These results indicate the associations of g.28470 T>C and g.28672 G>A with meat quality traits in Qinchuan cattle. Thus, the FATP1 gene may be used in marker-assisted selection of beef cattle in breeding programs.

Clinical comparison of antrum-preserving double tract reconstruction vs roux-en-Y reconstruction after gastrectomy for Siewert types II and III adenocarcinoma of the esophagogastric junction

AIM: To explore a reasonable method of digestive tract reconstruction, namely, antrum-preserving double-tract reconstruction (ADTR), for patients with adenocarcinoma of the esophagogastric junction (AEG) and to assess its efficacy and safety in terms of long-term survival, complications, morbidity and mortality.

METHODS: A total of 55 cases were retrospectively collected, including 18 cases undergoing ADTR and 37 cases of Roux-en-Y reconstruction (RY) for AEG (Siewert types II and III) at North Sichuan Medical College. The cases were divided into two groups. The clinicopathological characteristics, perioperative outcomes, postoperative complications, morbidity and overall survival (OS) were compared for the two different reconstruction methods.

RESULTS: Basic characteristics including sex, age, body mass index (BMI), Siewert type, pT status, pN stage, and lymph node metastasis were similar in the two groups. No significant differences were found between the two groups in terms of perioperative outcomes (including the length of postoperative hospital stay, operating time, and intraoperative blood loss) and postoperative complications (consisting of anastomosis-related complications, wound infection, respiratory infection, pleural effusion, lymphorrhagia, and cholelithiasis). For the ADTR group, perioperative recovery indexes such as time to first flatus (P = 0.002) and time to resuming a liquid diet (P = 0.001) were faster than those for the RY group. Moreover, the incidence of reflux esophagitis was significantly decreased compared with the RY group (P = 0.048). The postoperative morbidity and mortality rates for overall postoperative complications and the rates of tumor recurrence and metastasis were not significantly different between the two groups. Survival curves plotted using the Kaplan-Meier method and compared by log-rank test demonstrated similar outcomes for the ADTR and RY groups. Multivariate analysis of significantly different factors that presented as covariates on Cox regression analysis to assess the survival and recurrence among AEG patients showed that age, gender, BMI, pleural effusion, time to resuming a liquid diet, lymphorrhagia and tumor-node-metastasis stage were important prognostic factors for OS of AEG patients, whereas the selection of surgical method between ADTR and RY was shown to be a similar prognostic factor for OS of AEG patients.

CONCLUSION: ADTR by jejunal interposition presents similar rates of tumor recurrence, metastasis and long-term survival compared with classical reconstruction with RY esophagojejunostomy; however, it offers considerably improved near-term quality of life, especially in terms of early recovery and decreased reflux esophagitis. Thus, ADTR is recommended as a worthwhile digestive tract reconstruction method for Siewert types II and III AEG.

Characterization of novel microsatellite markers for Hyphantria cunea and implications for other Lepidoptera

This is the first report of microsatellite markers (simple sequence repeats, SSR) for fall webworm, Hyphantria cunea (Drury) (Lepidoptera: Arctiidae), an important quarantine pest in some European and Asian countries. Here, we developed 48 microsatellite markers for H. cunea from SSR enrichment libraries. Sequences isolated from libraries were sorted into four categories and analyzed. Our results suggest that sequences classified as Grouped should not be used for microsatellite primer design. The genetic diversity of microsatellite loci was assessed in 72 individuals from three populations. The number of alleles per locus ranged from 2 to 5 with an average of 3. The observed and expected heterozygosities of loci ranged from 0 to 0.958 and 0 to 0.773, respectively. A total of 18 out of 153 locus/population combinations deviated significantly from Hardy-Weinberg equilibrium. Moreover, significant linkage disequilibrium was detected in one pair of loci (1275 pairs in total). In the neutral test, two loci were grouped into the candidate category for positive selection and the remainder into the neutral category. In addition, a complex mutation pattern was observed for these loci, and F ST performed better than did R ST for the estimation of population differentiation in different mutation patterns. The results of the present study can be used for population genetic studies of H. cunea.

Association of SIRT2 gene polymorphisms with body measurement and growth traits of Qinchuan cattle

Silent information regulator 2 (SIRT2), a member of the Sirtuin family of class III nicotinamide adenine dinucleotide-dependent protein deacetylases, plays an important role in senescence, metabolism, and apoptosis. This study was conducted to detect potential polymorphisms of the bovine SIRT2 gene and explore their relationships with meat quality and body measurement traits (BMTs) in Qinchuan cattle. Four single nucleotide polymorphisms (A7445G, C7711T, G17937A, and G20937A) in the fourth intron, fourth exon, ninth exon, and twelfth exon of the SIRT2 gene, respectively, were identified according to the sequencing results of 520 individuals of a Qinchuan cattle population. The genotypic distributions of both A7445G and G20937A were in agreement with the Hardy-Weinberg equilibrium (P < 0.05), whereas the other two mutations were not (0.05 < P < 0.01), based on the X(2) test. Association analysis indicated that the four loci were significantly correlated with several BMTs and meat quality traits. When in combination, the H1H1 (AA-CC-GG-CC) diplotypes showed better BMT and meat quality traits than those by other combinations. Collectively, the results show that SIRT2 is involved in the regulation of the growth and meat quality of cattle, suggesting that the SIRT2 gene may be a candidate gene for marker-assisted selection in the development of future breeding programs for Qinchuan cattle.

The working experiences of novice psychiatric nurses in Taiwanese culture: a phenomenological study

Novice psychiatric nurses experience heavy workloads, insufficient training and support in Taiwan. The aim of this study was to understand the working experiences of novice psychiatric nurses during their first year in a clinical setting. A qualitative phenomenological approach, using semi-structured face-to-face interviews was used. Narratives were analyzed using Colaizzi's seven-step method. Data saturation was reached after interviews were conducted with 15 nurses based on the purposive sampling. Four themes and eight sub-themes were identified: struggling (lacking a sense of security and competency), emulating (learning the process of interaction with clients and families, learning an appropriate role from nursing staff), prevailing (developing core competency, creating a therapeutic environment) and belonging (coping with the job, becoming a part of the psychiatric nursing staff). The findings from this study demonstrate that nurses are often inadequately prepared for psychiatric nursing. They have little understanding of mental illness, are unable to communicate appropriately with clients and struggle to cope with the conditions. Our study supports the importance for helping nurses to improve their essential knowledge and skills for coping with the job and providing good quality care, particularly in the first year.

Recruitment of patients into an internet-based clinical trials database: the experience of OncoLink and the National Colorectal Cancer Research Alliance

PURPOSE

In March 2001, the National Colorectal Cancer Research Alliance (NCCRA) and OncoLink (http://www.oncolink.org) established a database to facilitate patient enrollment onto clinical trials. This study describes the population registering with the database and identifies discrepancies between individuals registering through the Internet and those registering through a telephone call center.

METHODS

Participants registered with the NCCRA/OncoLink database through the Internet or a telephone call center. All participants entering the database completed a questionnaire regarding basic demographics, colon cancer risk factors, and indicated how they became aware of the database. Comparisons were made between individuals registering through the Internet and those registering through the telephone call center.

RESULTS

A total of 2,162 participants registered during the first 16 months of the database. Most patients registered through the Internet rather than the telephone call center (88% v 12%; P < .001). More females than males registered (73% v 27%; P < .001). The majority (89%) were white. Participants registering through the Internet were younger than those registering through the call center (mean, 48.8 v 55.0 years; P < .001). There was no difference between the two groups with regard to sex or ethnicity.

CONCLUSION

The Internet has the potential to increase the likelihood that interested individuals find appropriate clinical trials. Some of the discrepancies that are known to exist for access to the Internet were also seen for those registering with the database through the Internet. Despite these differences, the potential to increase clinical trial enrollment with this type of Internet-based database is high.

Dose-dependent differences in the profile of mutations induced by carcinogenic (R,S,S,R) bay- and fjord-region diol epoxides of polycyclic aromatic hydrocarbons

Chinese hamster V79 cells were exposed to a high or low concentration of the highly carcinogenic (R,S,S,R) or the less active (S,R,R,S) bay- or fjord-region diol epoxides of benzo[a]pyrene, benzo[c]phenanthrene or dibenz[c,h]acridine. Independent 8-azaguanine-resistant clones were isolated, and base substitutions at the hypoxanthine (guanine) phosphoribosyltransferase (hprt) locus were determined. For the three (R,S,S,R) diol epoxides studied, the proportion of mutations at AT base pairs increased as the concentration of diol epoxide decreased. Concentration-dependent differences in the mutational profile were not observed, however, for the three (S,R,R,S) diol epoxides. In studies, with V-H1 cells (a DNA repair deficient variant of V79 cells), a concentration-dependent difference in the profile of mutations for the (R,S,S,R) diol epoxide of benzo[a]pyrene was not observed. These results suggest that concentration-dependent differences in the mutational profile are dependent on an intact DNA repair system. In additional studies, we initiated mouse skin with a high or low dose of benzo[a]pyrene and promoted the mice for 26 weeks with 12-O-tetradecanoylphorbol-13-acetate. Papillomas were examined for mutations in the c-Ha-ras proto-oncogene. Dose-dependent differences in the profile of c-Ha-ras mutations in the tumors were observed. In summary, (i) dose-dependent differences in mutational profiles at the hprt locus were observed in Chinese hamster V79 cells treated with several highly mutagenic and carcinogenic (R,S,S,R) bay- or fjord-region diol epoxides but not with their less active (S,R,R,S) diol epoxide enantiomers, (ii) a dose-dependent difference in the mutational profile was not observed for the (R,S,S,R) diol epoxide of benzo[a]pyrene in a DNA-repair defective V79 cell line, and (iii) a dose-dependent difference in the mutational profile in the c-Ha-ras proto-oncogene was observed in tumors from mice treated with a high or low dose of benzo[a]pyrene.

Indomethacin lowers the threshold thermal exposure for hyperthermic radiosensitization and heat-shock inhibition of ionizing radiation-induced activation of NF-kappaB

PURPOSE

It is well established that salicylate and several other non-steroidal anti-inflammatory agents (NSAID), including indomethacin, can activate the heat-shock response, albeit at high concentrations. This is significant since heat shock significantly alters the cellular cytotoxic response to ionizing radiation (IR). It was previously shown that heat shock, as well as NSAIDs, inhibits IR-induced activation of NF-kappaB and that NF-kappaB protects against IR-induced cytotoxicity. Hence, it is hypothesized that pretreatment with indomethacin before heating will lower the temperature and heating times required to inhibit the activation of NF-kappaB and induce significant hyperthermic radiosensitization.

MATERIALS AND METHODS

Experiments were performed in HeLa cell lines and the DNA-binding activity was determined by EMSA. Cellular radiosensitivity was determined by clonogenic assay.

RESULTS

HeLa cells pretreated with indomethacin showed a decrease in the temperature-time combination necessary to inhibit IR-induction of NF-kappaB DNA binding. In addition, clonogenic cell survival assays using identical conditions showed an indomethacin dose-dependent enhancement of hyperthermic radiosensitization. Thus, similar concentrations of indomethacin both lowered the threshold thermal exposure to inhibit activation of NF-kappaB DNA-binding and increased the sensitivity of tumour cells to hyperthermic radiosensitization-induced cytotoxicity. In HeLa cells treated with N-alpha-tosylphenylalanyl-chloromethyl ketone (TPCK), a serine protease inhibitor that blocks activation of NF-kappaB, an increase in radiosensitivity was observed. Interestingly, no additional cell killing was observed when heat shock was added to cells treated with TPCK before IR, suggesting a possible common cytotoxic pathway.

CONCLUSIONS

The results demonstrate that indomethacin lowers the temperature-time conbination necessary to induce several physiological processes associated with the heat-shock response. Furthermore, NSAID may be potential adjuvants in improving the clinical effectiveness of hyperthermia in radiation therapy.

[Effect of nerve growth factor on the visual evoked potential of rats pretreated by CS2]

AIM

To study the therapeutic effect of NGF to rats with newly CS2 deranged.

METHODS

The model of rats with deranged visual nerve was made by CS2 (i.p) for three weeks. Rats were then treated with different dosages of NGF for three weeks, and the changes of visual evoked potential were determined.

RESULTS

The latency of PREP and FEP shortened significantly vs control after treatment for 10 and 20 days.

CONCLUSION

NGF can improve the conductivity of visual with dose-effect relationship, suggesting that NGF has a significant therapeutic effect on the deranged visual nerve.

Indomethacin-induced radiosensitization and inhibition of ionizing radiation-induced NF-kappaB activation in HeLa cells occur via a mechanism involving p38 MAP kinase

Although ionizing radiation (IR) activates multiple cellular factors that vary depending on dose and tissue specificity, the activation of NF-kappaB appears to be a well-conserved response in tumor cells exposed to IR. Recently, it also has been demonstrated that nonsteroidal anti-inflammatory agents inhibit tumor necrosis factor and interleukin-1-induced NF-kappaB activation and act as radiosensitizing agents. These observations reinforce the growing notion that NF-kappaB may be a protective cellular factor responding to the cytotoxicity of IR and other damaging stimuli. As such, we addressed the idea and mechanism that NF-kappaB is a downstream target of the nonsteroidal anti-inflammatory agent indomethacin and is involved in the process of radiosensitization. In this study, we report that indomethacin inhibited IR-induced activation of NF-kappaB and sensitized HeLa cells to IR-induced cytotoxicity at similar concentrations. Pretreatment of HeLa cells with SB 203580, a pyridinyl imidazole compound that specifically inhibits p38 mitogen-activated protein kinase (MAPK), abrogated the ability of indomethacin to inhibit IR-induced activation of NF-kappaB and diminished the indomethacin radiosensitizing effect. In addition, the transient genetic activation of p38(MAPK) inhibited IR induction of NF-kappaB gene expression in the absence of indomethacin. Finally, permanently transfected cell lines genetically unable to activate NF-kappaB, because of expression of a dominant negative I-kappaBalpha gene, demonstrated increased sensitivity to IR-induced cytotoxicity. Taken together, these results suggest that p38 MAPK is a target involved in indomethacin-induced radiosensitization and that NF-kappaB may be one downstream target in this process.

Tumor invasiveness and liver metastasis of colon cancer cells correlated with cyclooxygenase-2 (COX-2) expression and inhibited by a COX-2-selective inhibitor, etodolac

Non-steroidal anti-inflammatory drugs (NSAIDs) have been reported to reduce the risk and mortality of colorectal cancer (CRC). Although the exact mechanisms remain unclear, the inhibition of cyclooxygenase (COX) by NSAIDs appears to abort, if not prevent, CRC carcinogenesis or metastatic tumor progression. The aim of our study was to investigate the association between COX-2 expression and CRC tumor cell invasiveness. The differences in immunoblot-detectable COX-2 protein contents in primary CRCs, metastatic hepatic lesions and corresponding normal mucosa from the same individual were evaluated in 17 patients. Three different colon cancer cell lines, SW620, Lovo, HT-29 and a metastatic variant of HT-29, HT-29/Inv3, were employed to evaluate COX-2 expression and prostaglandin E(2) (PGE2) production in relation to their invasive abilities in vitro. The effects of a COX-2-selective inhibitor, etodolac, on cell proliferation and invasive activity were also determined. The results showed that 15 of 17 (88%) metastatic CRC cells from the liver and 14 of 17 (82%) primary CRC tissue exhibited much higher levels of COX-2 than corresponding adjacent normal mucosa from the same patient. Among those patients with relatively high COX-2 expression in the primary tumors, almost all exhibited even higher levels of COX-2 in their hepatic metastases. Among the 4 colon cancer cell lines, HT-29/Inv3 manifested the highest COX-2 expression, PGE2 production and in vitro invasive activity. The selective COX-2 inhibitor, etodolac, could especially exert cytotoxicity and markedly suppress the invasive property and PGE(2) production, although not the COX-2 protein level, in HT-29/Inv3 cells. Our results imply that COX-2 expression may be associated with the invasive and metastatic properties of CRC tumor cells.

Increased activator protein 1 activity as well as resistance to heat-induced radiosensitization, hydrogen peroxide, and cisplatin are inhibited by indomethacin in oxidative stress-resistant cells

It has been established that tumor cells develop resistance to a variety of therapeutic agents after multiple exposures to these agents/drugs. Many of these therapeutic agents also appear to increase the activity of transcription factors, such as activator protein 1 (AP-1), believed to be involved in cellular responses to oxidative stress. Therefore, we hypothesized that cellular resistance to cancer therapeutic agents may involve the increased activity of transcription factors that govern resistance to oxidative stress, such as AP-1. To investigate this hypothesis, a previously characterized cisplatin, hyperthermia, and oxidative stress-resistant Chinese hamster fibroblast cell line, OC-14, was compared to the parental HA-1 cell line. Electrophoretic mobility shift and Western blot assays performed on extracts isolated from OC-14 cells demonstrated a 10-fold increase in constitutive AP-1 DNA-binding activity as well as increased constitutive c-Fos and c-Jun immunoreactive protein relative to HA-1 cells. Treatment of OC-14 cells with indomethacin inhibited constitutive increases in AP-1 DNA-binding activity and c-Fos/c-Jun-immunoreactive protein levels. Clonogenic survival assays demonstrated that pretreatment with indomethacin, at concentrations that inhibited AP-1 activity, significantly reduced the resistance of OC-14 cells to heat-induced radiosensitization, hydrogen peroxide, and cisplatin. These results demonstrate a relationship between increases in AP-1 DNA-binding activity and increased cellular resistance to cancer therapeutic agents and oxidative stress that is inhibited by indomethacin. These results support the hypothesis that inhibition of AP-1 activity with nonsteroidal anti-inflammatory drugs, such as indomethacin, may represent a useful adjuvant to cancer therapy.

Tumor invasiveness and liver metastasis of colon cancer cells correlated with cyclooxygenase-2 (COX-2) expression and inhibited by a COX-2-selective inhibitor, etodolac

Non-steroidal anti-inflammatory drugs (NSAIDs) have been reported to reduce the risk and mortality of colorectal cancer (CRC). Although the exact mechanisms remain unclear, the inhibition of cyclooxygenase (COX) by NSAIDs appears to abort, if not prevent, CRC carcinogenesis or metastatic tumor progression. The aim of our study was to investigate the association between COX-2 expression and CRC tumor cell invasiveness. The differences in immunoblot-detectable COX-2 protein contents in primary CRCs, metastatic hepatic lesions and corresponding normal mucosa from the same individual were evaluated in 17 patients. Three different colon cancer cell lines, SW620, Lovo, HT-29 and a metastatic variant of HT-29, HT-29/Inv3, were employed to evaluate COX-2 expression and prostaglandin E(2) (PGE2) production in relation to their invasive abilities in vitro. The effects of a COX-2-selective inhibitor, etodolac, on cell proliferation and invasive activity were also determined. The results showed that 15 of 17 (88%) metastatic CRC cells from the liver and 14 of 17 (82%) primary CRC tissue exhibited much higher levels of COX-2 than corresponding adjacent normal mucosa from the same patient. Among those patients with relatively high COX-2 expression in the primary tumors, almost all exhibited even higher levels of COX-2 in their hepatic metastases. Among the 4 colon cancer cell lines, HT-29/Inv3 manifested the highest COX-2 expression, PGE2 production and in vitro invasive activity. The selective COX-2 inhibitor, etodolac, could especially exert cytotoxicity and markedly suppress the invasive property and PGE(2) production, although not the COX-2 protein level, in HT-29/Inv3 cells. Our results imply that COX-2 expression may be associated with the invasive and metastatic properties of CRC tumor cells.

Thioredoxin nuclear translocation and interaction with redox factor-1 activates the activator protein-1 transcription factor in response to ionizing radiation

Thioredoxin (TRX) is a cytoplasmic, redox-sensitive signaling factor believed to participate in the regulation of nuclear transcription factors mediating cellular responses to environmental stress. Activation of the activator protein (AP)-1 transcription factor is thought to be mediated in part by redox-sensitive interactions between the nuclear signaling protein redox factor-1 (Ref-1) and TRX. In this study, the role of TRX and Ref-1 in the activation of the AP-1 complex was examined in HeLa and Jurkat cell lines exposed to ionizing radiation (IR). After exposure to IR, nuclear levels of immunoreactive TRX increased, accompanied by an increase in AP-1 DNA binding activity. It was shown that a physical interaction between Ref-1 and TRX occurs within the nucleus and is enhanced after exposure to IR. Furthermore, TRX immunoprecipitated from irradiated cells was capable of activating AP-1 DNA binding activity in nonirradiated nuclear extracts. In addition, immunodepletion of Ref-1 from nuclear extracts demonstrated that the increase in AP-1 DNA binding activity after IR was also dependent upon the presence of Ref-1 from irradiated cells. Finally, the ability of both TRX and Ref-1 from irradiated cells to stimulate AP-1 DNA binding in nonirradiated nuclear extracts was abolished by chemical oxidation and restored by chemical reduction. These results indicate that, in response to IR, TRX and Ref-1 undergo changes in redox state that contribute to the activation of AP-1 DNA binding activity. These experiments suggest that a redox-sensitive signaling pathway leading from TRX to Ref-1 to the AP-1 complex participates in the up-regulation of DNA binding activity in response to ionizing radiation.

PIK3CA as an oncogene in cervical cancer

Amplification of chromosome arm 3q is the most consistent aberration in cervical cancer, and is implicated in the progression of dysplastic uterine cervical cells into invasive cancer. The present study employed the 'positional candidate gene' strategy to determine the contribution of PIK3CA, which is located in 3q26.3, in cervical tumorigenesis. PIK3CA is known to be involved in the PI 3-kinase/AKT signaling pathway, which plays an important role in regulating cell growth and apoptosis. The results of comparative genomic hybridization show that the 3q26.3 amplification was the most consistent chromosomal aberration in primary tissues of cervical carcinoma, and a positive correlation between an increased copy number of PIK3CA (detected by competitive PCR) and 3q26.3 amplification was found in tumor tissues and in cervical cancer cell lines. In cervical cancer cell lines harboring amplified PIK3CA, the expression of gene product (p110alpha) of PIK3CA was increased, and was subsequently associated with high kinase activity. In addition, transformation phenotypes in these lines, including increased cell growth and decreased apoptosis, were found to be significantly affected by the treatment of specific PI 3-kinase inhibitor, suggesting that increased expression of PIK3CA in cervical cancer may result in promoting cell proliferation and reducing apoptosis. These evidences support that PIK3CA is an oncogene in cervical cancer and PIK3CA amplification may be linked to cervical tumorigenesis. Oncogene (2000).

Characterization of the mutational profile of (+)-7R,8S-dihydroxy-9S, 10R-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene at the hypoxanthine (guanine) phosphoribosyltransferase gene in repair-deficient Chinese hamster V-H1 cells

Earlier studies have shown that the profile of mutations induced by (+)-7R,8S-dihydroxy-9S,10R-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (+)-BPDE at the hypoxanthine (guanine) phosphoribosyltransferase (hprt) gene of Chinese hamster V79 cells was dependent on the concentration of (+)-BPDE. In the present study, we examined the effect of the concentration of (+)-BPDE on its mutational profile at the hprt gene in repair-deficient V-H1 cells (a derivative of V79 cells) to explore the role of DNA repair in the dose-dependent mutational profile of (+)-BPDE. Independent hprt mutant clones were isolated after exposing V-H1 cells to dimethylsulfoxide (DMSO) or to low (4-6 nM; 95% cell survival) or high (40-48 nM; 31% cell survival) concentrations of (+)-BPDE in DMSO. The mutation frequencies for the DMSO control and for the low and high concentration groups were 0.1, 2.1 and 32.9 mutant colonies/10(5) survivors, respectively. The profile of mutations at the hprt gene was characterized for 148 (+)-BPDE-induced mutant clones and the results from the present study were compared with those obtained earlier with V79 cells. The data indicated that: (i) V-H1 cells were approximately 9-fold more sensitive to the cytotoxic effects of (+)-BPDE than V79 cells; (ii) the mutation frequency in V-H1 cells was similar to that observed in V79 cells following exposure to similar concentrations of (+)-BPDE; (iii) (+)-BPDE-induced mutations at guanine on the transcribed strand of the hprt gene were common in V-H1 cells but were extraordinarily rare in V79 cells; (iv) (+)-BPDE-induced mutations at adenine on the transcribed strand of the hprt gene were common in both V-H1 and V79 cells; (v) although exposure of V79 cells to different doses of (+)-BPDE resulted in a dose-dependent mutational profile at the hprt gene, this was not observed in V-H1 cells. Our observations indicate a defect in the transcription-coupled repair of (+)-BPDE-DNA adducts in V-H1 cells and that the repair activity deficient in V-H1 cells is essential for the dose-dependent mutational profile observed with (+)-BPDE in V79 cells.

Gene therapy with tumor vaccine increases the survival of hepatoma-bearing mice

BACKGROUND

Tumor vaccines combined with cytokine gene therapy and Bacillus Calmette-Guérin (BCG) were tested for prevention and therapeutic effects in the H6 mouse hepatoma model.

METHODS

Plasmid DNA of expression vectors carrying cDNA of mouse interleukin (IL)-2 and mouse granulocyte-macrophage colony-stimulating factor (mGM-CSF) were used for transfection to obtain H6 mouse hepatoma cells that secreted IL-2 (H6/IL-2) or GM-CSF (H6/GM-CSF). For tumor prevention, groups of mice were immunized twice with irradiated tumor cells with untransduced H6, H6/IL-2, H6/GM-CSF, or an equal mixture of H6/IL-2 and H6/GM-CSF. Three weeks later, these mice were inoculated subcutaneously with live H6 hepatoma cells, and tumor growth was measured. For therapeutic studies, mice first inoculated with live H6 cells were treated three days later with various irradiated tumor cell vaccines alone or in combination with BCG. Subsequent tumor growth was measured.

RESULTS

In tumor prevention studies, significant protection from tumor growth has been observed in animals vaccinated with irradiated cytokine-secreting H6 cells compared with those immunized with irradiated parental H6 cells. In tumor therapy studies, subsequent administration of irradiated H6/GM-CSF cells in combination with BCG impeded the tumorigenicity of preinoculated live H6 hepatoma cells.

CONCLUSIONS

These results suggest that cytokine-secreting tumor vaccines have a prophylactic effect and BCG, in combination with irradiated H6/GM-CSF cells, shows a synergistic effect on delaying the growth of H6 mouse hepatomas.

Dose-dependent mutation profile in the c-Ha-ras proto-oncogene of skin tumors in mice initiated with benzo[a]pyrene

Female CD-1 mice were treated topically with a low (25-50 nmol) or high (800 nmol) dose of benzo[a]pyrene (BP) or acetone vehicle, followed by 5 nmol 12-O-tetradecanoylphorbol 13-acetate (TPA) twice a week for 26 weeks. Selective UV radiation fractionation followed by PCR methods were used to analyze histologically defined subsets of cells (approximately 100-200 cells) on formalin-fixed, paraffin-embedded and H&E stained microscope sections. DNA samples from normal-appearing, hyperplastic or tumor regions from the skin of animals from each treatment group were isolated and amplified by PCR with c-Ha-ras-specific primers. Single-strand conformation polymorphism (SSCP) analyses were performed on both exon 1 and 2 products from each sample. DNA extracted from each aberrant band of SSCP analyses was amplified by PCR for further sequence analysis. The data indicate that c-Ha-ras mutations can be detected in normal-looking and hyperplastic epidermal cells as well as in tumor cells obtained from mice initiated with BP and promoted with TPA. The frequencies of c-Ha-ras mutations for normal-looking, hyperplastic and tumor samples were 3/20 (15%), 8/17 (47%) and 58/68 (85%), respectively, for the low dose group and 8/18 (44%), 10/20 (50%) and 64/86 (74%), respectively, for the high dose group. These observations indicate that there were no dose dependencies in the mutation frequencies for normal-looking, hyperplastic and tumor samples. For combined high dose and low dose samples, differences in mutation frequencies of the c-Ha-ras gene between the normal-looking, hyperplastic and tumor samples were highly significant (P < 0.0001, Fisher's exact test). All mutations detected were located at codons 12, 13 and 61 of the c-Ha-ras gene. With the numbers in parentheses indicating the nucleotide position in the coding sequence of the c-Ha-ras proto-oncogene, the distributions of mutations for G-->A (35), G-->T (35), G-->C (37), G-->T (38), C-->A (181), A-->T (182) and A-->G (182) in the low dose tumors were 5, 2, 11, 74, 0, 7 and 2%, respectively, and the distribution of mutations in tumors from animals treated with a high dose of BP were 3, 7, 13, 61, 15, 1 and 0%, respectively. Differences in the global mutation spectra (site and kind of all mutations) for the c-Ha-ras gene between the high and low dose group tumors were statistically significant (P < 0.004, Fisher's exact test) and the major difference between these two groups was C-->A (181) base substitutions. In summary, our data indicate that: (i) 79% of the BP/TPA skin tumors in CD-1 mice had c-Ha-ras mutations for the combined data for high dose and low dose tumors; (ii) the major mutations detected in BP/TPA skin tumors were G-->T transversions; (iii) the global mutation profile in the c-Ha-ras proto-oncogene in skin tumors obtained after initiation with a low dose of BP was different from that obtained after initiation with a high dose of BP.

The ratio of deoxyadenosine to deoxyguanosine adducts formed by (+)-(7R,8S,9S,10R)-7,8-dihydroxy-9,10-epoxy-7,8,9,10- tetrahydrobenzo[a]pyrene in purified calf thymus DNA and DNA in V-79 cells is independent of dose

The hypothesis that the decrease in the proportion of mutations at AT base pairs in Chinese hamster V-79 cells treated with increasing doses of (+)-(R,S,S,R)-benzo[a]pyrene diol epoxide ((+)-BPDE) is due to saturation of A <hot spots> for adduct formation was investigated by comparing the ratio of dA to dG adducts formed at high (0.48 microM) and low (0.04 microM) doses of [3H]-labeled (+)-BPDE. The dA to dG adduct ratio was similar in both calf thymus DNA and the genomic DNA in V-79 cells, and did not change with dose. For the V-79 cells, this ratio was also unaffected by a 24-h post treatment repair incubation.

Involvement of Fas (CD95/APO-1) and Fas ligand in apoptosis induced by ganciclovir treatment of tumor cells transduced with herpes simplex virus thymidine kinase

Transduction of cancer cells with herpes simplex virus thymidine kinase gene (HSVtk) followed by prodrug ganciclovir (GCV) treatment has been shown to induce apoptosis. In this study, four murine tumors including B16F10 melanoma, NG4TL4 sarcoma, H6 hepatoma and 1MEA 7R.1 hepatoma were found to vary in sensitivity to this gene therapy strategy in vitro but, at effective doses of GCV, the HSVtk-transduced cells of all four tumors showed similar kinetics of early rise in p53 protein levels, then cell cycle S-/G2-phase arrest and finally signs of apoptosis. Immunoblot analyses revealed that Fas (CD95/APO-1), Fas ligand (FasL) and two downstream mediators, RIP and caspase-3, (CPP32, YAMA, Apopain) were increased in GCV-treated HSVtk-transduced tumor cells the cell cycle arrest and before apoptosis. Increased expression of FasL could also be observed in vivo in HSVtk-transduced tumors induced to regress by GCV treatment. Enzyme measurements using specific substrate showed that the caspase-3 activation followed kinetically the FasL expression. More than half of the HSVtk/GCV-induced cell death could be abrogated by addition to the cell culture medium of a specific antisense oligonucleotide to block FasL synthesis, a recombinant Fas/Fc chimeric protein to compete with Fas receptor for FasL binding, or cell-permeable specific tetrapeptide inhibitors of caspase-3 or caspase-8.

S- and G2-phase cell cycle arrests and apoptosis induced by ganciclovir in murine melanoma cells transduced with herpes simplex virus thymidine kinase

Mechanism of cell killing by transfer of Herpes simplex virus type-1 thymidine kinase (HSVtk) and subsequent ganciclovir (GCV) treatment was examined in B16F10 murine melanoma model. While parental B16F10 melanoma cells were resistant to GCV at 100 microM or higher, HSVtk-transduced B16F10 melanoma cell clones became susceptible to GCV with IC50 of 0.1 to 0.3 microM. By means of various parameters including characteristic morphological changes, in situ DNA end-labeling, DNA ladder pattern, flow cytometric detection of sub-G1 DNA content, and annexin V binding of inverted cell surface phosphatidylserine, apoptosis was shown to be associated with the cell killing of ganciclovir on HSVtk-transduced melanoma B16F10 cells. Kinetic analysis showed that the signs of apoptosis were observed not until 60 h of continued GCV treatment and preceded first by a rise in p53 protein level in 12 h and then by S-phase/G2-phase cell cycle arrest associated with corresponding increases in the level of cyclin B1 protein but no apparent change in protein level of Bax or Cdc2. These results suggest that apoptosis occurred as a result of ganciclovir-induced cell cycle arrests rather than direct chemical effect on HSVtk-transduced B16F10 melanoma cells.

Paradoxical effect of GM-CSF gene transfer on the tumorigenicity and immunogenicity of murine tumors

The effect of granulocyte/macrophage colony-stimulating factor (GM-CSF) gene transfer on the tumorigenicity and immunogenicity of 2 different murine tumor lines was determined. Transduction of B16 melanoma cells with the GM-CSF gene rendered the cells more immunogenic. In contrast, transduction of NG4TL4 fibrosarcoma in FVB/N mice (NG) with the GM-CSF gene showed increased tumorigenicity in a high producer line (NG-MGh). The parent NG or NG-MG cells induced the same level of cytotoxic T-lymphocyte (CTL) response and the same magnitude of tumor transplantation immunity. However, the proliferation of the NG-MGh cells was increased 2- to 10-fold. There was no increase in apoptosis in the NG cells and there was no increase of NG-MGh cells in S-phase, hence the increase of the proliferative activity appeared to be indeed inherent to the cells. Mixing the splenocytes from the NG-MGh tumor bearers with the NG tumor cells did not increase tumorigenicity but totally inhibited the growth of the NG tumor, indicating that suppressor cells were not present. Mixing 10,000 rad X-irradiated NG-MGh cells with viable NG tumor cells resulted in 3- to 10-fold increased NG tumor growth rate. The in vitro proliferation of NG cells was increased by adding both GM-CSFs and macrophages and not by either one alone, suggesting that interaction between macrophages and GM-CSFs resulted in the production of tumor growth enhancing factor(s). Our findings suggest that transduction of NG tumor cells with the GM-CSF gene increases tumorigenicity, which is attributed both to an increased inherent proliferative ability of the tumor cells and to the in vivo production of a tumor growth enhancing factor(s) at the tumor site.

[Effects of microinjection of sodium glutamate and glycine into ventrolateral nucleus of tractus solitarius on the discharges of phrenic nerve in rabbits]

The effects of microinjection of sodium glutamate and glycine into ventrolateral nucleus of tractus solitarius (VLNTS) on the discharges of phrenic nerve were observed on 40 anaesthetized, vagotomized, paralyzed and artificially ventilated rabbits. The results were as follows: Phrenic nerve discharges were increased, inspiratory duration prolonged, expiratory duration shortened and respiratory frequency not changed by microinjection of sodium glutamate into VLNTS. While by microinjection of glycine, phrenic nerve discharges were decreased, even abolished, inspiratory duration shortened, expiratory duration irregularly prolonged and respiratory frequency decreased. The above results show that VLNTS exert important effects on the genesis of respiratory rhythm.

Dose-dependent differences in the mutational profiles of (-)-(1R,2S,3S,4R)-3,4-dihydroxy-1, 2-epoxy-1,2,3,4-tetrahydrobenzo[c]phenanthrene and its less carcinogenic enantiomer

Chinese hamster V-79 cells were treated with high cytotoxic or low noncytotoxic concentrations of the highly carcinogenic and mutagenic (-)-(1R,2S,3S,4R)-3,4-dihydroxy-1, 2-epoxy-1,2,3,4-tetrahydrobenzo[c]phenanthrene [(-)-B[c]PhDE; fjord-region diol epoxide] or its biologically less active (+)-(1S,2R,3R,4S) enantiomer [(+)-B[c]PhDE]. The benzylic 4-hydroxyl group and the epoxide oxygen are trans in both enantiomers. Independent 8-azaguanine-resistant clones were isolated. The coding region of the hypoxanthine (guanine) phosphoribosyltransferase gene was amplified by reverse transcription-PCR and sequenced. For (-)-B[c]PhDE, mutation frequencies were 10- or 356-fold above background for the low (0.01-0.1 microM; 97% cell survival) or high (1.0-1.25 microM; 26% cell survival) doses, respectively. For the high dose group, 20 of 64 base substitutions occurred at GC base pairs (31%) and 44 at AT base pairs (69%). For the low-dose group, 6 of 55 base substitutions were at GC base pairs (11%), and 49 were at AT base pairs (89%). For the less active (+)-B[c]PhDE, mutation frequencies were 17- or 372-fold above background for the low (0.12-0.5 microM; 95% cell survival) or high (2.0-3.0 microM; 31% cell survival) doses, respectively. In contrast to the results with the (-)-B[c]PhDE, both the high- and the low-dose groups for (+)-B[c]PhDE gave a 50:50 distribution of base substitution at GC versus AT base pairs. Our data indicate that: (a) transversions were the predominant base substitutions observed for both the (+)- and (-)-enantiomers of B[c]PhDE; (b) (-)-B[c]PhDE showed high selectivity for causing AT --> TA transversions, whereas considerably less selectivity was observed for (+)-B[c]PhDE; (c) (-)-B[c]PhDE had a different hot spot profile for base substitutions than did (+)-B[c]PhDE, but some common hot spots were observed for both compounds; and (d) decreasing the dose of (-)-B[c]PhDE increased the proportion of mutations at AT base pairs and decreased those at GC base pairs, but this was not observed for (+)-B[c]PhDE.

[Effect of microinjection of sodium giutamate and glycine into ventrolateral nucleus of tractus solitarius on the evoked potentials of arcuatus nucleus in rabbits]

Experiments were performed on 66 anaesthetized, vagotomized, paralyzed and artificially ventilated rabbits. The effects of microinjection sodium glutamate and glycine into ventrolateral nucleus of tractus solitarius (VLNTS) on hypothalamic arcuatus nucleus evoked potentials were observed. The main results obtained were as follows: (1) Phrenic nerve discharges were increased and the amplitude of P2 and N2 waves of arcuatus nucleus evoked potentials were decreased by microinjection of sodium glutamate into VLNTS. Phrenic nerve discharges were decreased and the amplitude of P2 and N2 waves of arcuatus nucleus evoked potentials were increased by microinjection of glycine into VLNTS. (2) After intravenous injection of naloxone, the phrenic nerve discharges could still be excited by microinjection of sodium glutamate as before, but the effects on the amplitude of P2 and N2 waves of arcuatus nucleus evoked potentials, unlike that of sodium glutamate, were reversed. The results suggest that the excitatory action of respiratory neurons in the VILTS may affect on the sensory function of arcuatus nucleus. The mechanism involved was discussed.

Characterization of hprt splicing mutations induced by the ultimate carcinogenic metabolite of benzo[a]pyrene in Chinese hamster V-79 cells

The molecular basis for putative aberrant splicing of hypoxanthine (guanine) phosphoribosyltransferase (hprt) pre-mRNA in Chinese hamster V-79 cells was determined for 75 independent (+)-7R,8S-dihydroxy-9S,10R-epoxy-7,8,9,10-tetrahydrobenzo[a]-pyrene [(+)-BPDE]-induced and 6 spontaneous 8-azaguanine-resistant mutant clones that had exon deletions in their hprt cDNA. Genomic DNA fragments corresponding to the missing exons and their flanking intron regions were amplified by PCR and sequenced. The results indicated that each of these mutants generated a normal-sized PCR product and resulted from aberrant splicing. For (+)-BPDE-induced aberrant splicing mutants, 81% (61 of 75 clones) had base substitution mutations, 5% (4 of 75 clones) had a single base deletion, and 13% (10 of 75 clones) lacked a detectable mutation in the skipped exon, its flanking intron sequences, or in the upstream donor site of the preceding intron. All mutations at a splice donor site resulted in skipping of the entire upstream neighboring exon, whereas alterations at a splice acceptor site caused skipping of the downstream neighboring exon or activation of a cryptic acceptor site in the downstream exon. Fifty-nine % of the splicing mutants had a mutation occurring at the splice site consensus sequence in the intron, and 28% of the splicing mutants had mutations within exon sequences. Among 21 aberrant splicing mutant clones with a mutation inside an exon sequence, seven were in exon 2, two were in exon 3, and twelve were in exon 4. Evidence is presented that a stemloop structure sequesters the splice donor site of exon 2 in pre-mRNA and plays a role in exon 2 skipping. Mutant clones with mutations stabilizing the proposed stemloop structure inhibited the use of the normal exon 2 splice site which resulted in exon 2 skipping in the hprt mRNA. These mutant clones expressed a mixed population of mRNAs, and both normal-sized and truncated mRNA were formed. Similar to our earlier finding that treatment of V-79 cells with (+)-BPDE resulted in a dose-dependent mutation profile within the coding region of the hprt gene, we also observed the presence of dose-dependence in the profile of (+)-BPDE-induced base substitutions in aberrant splicing mutants. As the dose of (+)-BPDE was decreased, the proportion of base substitution mutations at AT base pairs that affected RNA splicing was increased.

Mutagenic selectivity at the HPRT locus in V-79 cells: comparison of mutations caused by bay-region benzo[a]pyrene 7,8-diol-9,-10-epoxide enantiomers with high and low carcinogenic activity

Earlier studies from our laboratories characterized the mutation profile of the optically active (+)-7R,8S-dihydroxy-9S,10R-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene [(+)-BPDE--the ultimate carcinogenic metabolite of benzo[a]pyrene] in the coding region of the hypoxanthine (guanine) phosphoribosyltransferase (HPRT) gene of Chinese hamster V-79 cells. In the present study, we evaluated the mutation profile of (-)-7S,8R-dihydroxy-9R, 10S-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene [(-)-BPDE-a weakly carcinogenic or inactive enantiomer] and compared its mutation profile with that of (+)-BPDE. In both diol epoxide enantiomers, the benzylic 7-hydroxy group and epoxide oxygen are trans. The mutation frequency for V-79 cells treated with DMSO vehicle or with a low, non-cytotoxic dose (0.5 microM) or a high cytotoxic dose (2.0 microM) of (-)-BPDE was 1, 25 or 185 8-azaguanine-resistant colonies/10(5) survivors, respectively. Independent 8-azaguanine-resistant clones were isolated, and complementary DNAs were prepared by reverse transcription. The coding region of the HPRT gene was amplified by the polymerase chain reaction and sequenced. Altogether, 92 (-)-BPDE-induced mutant clones were examined. At both doses, base substitutions were the most prevalent mutations observed (present in approximately 7% of the mutant clones), followed by exon deletions (present in approximately 22% of the mutant clones) and frame shift mutations (present in approximately 6% of the mutant clones) in the cDNAs analyzed. At the high cytotoxic dose, 5 out of 36 base substitutions occurred at AT base pairs (14%) and 31 at GC base pairs (86%). At the low, non-cytotoxic dose, 7 out of 34 base substitutions were at AT base pairs (21%) and 27 were at GC base pairs (79%). Although there was a trend towards an increase in the proportion of mutations at AT base pairs when the dose of (-)-BPDE was decreased, this trend was not statistically significant. The data also indicated no dose-dependent differences in the kinds of base substitutions or exon deletions in cDNAs induced by (-)-BPDE. Ninety-one per cent of the (-)-BPDE-induced mutations that occurred at guanine were on the non-transcribed strand of DNA and 9% were on the transcribed strand. In contrast to these results, 50% of the (-)-BPDE-induced mutations that occurred at adenine were on the transcribed strand and 50% on the non-transcribed strand.(ABSTRACT TRUNCATED AT 400 WORDS)

Dose-dependent differences in the profile of mutations induced by (+)-7R,8S-dihydroxy-9S,10R-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene in the coding region of the hypoxanthine (guanine) phosphoribosyltransferase gene in Chinese hamster V-79 cells

Chinese hamster V-79 cells were exposed to a high dose (0.30-0.48 microM; 32% cell survival), an intermediate dose (0.04-0.10 microM; 100% cell survival) or a low dose (0.01-0.02 microM; 97% cell survival) of (+)-7R,8S-dihydroxy-9S,10R-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene [(+)-BPDE] which is the ultimate carcinogenic metabolite of benzo(a)pyrene. The mutation frequency for cells treated with dimethyl sulfoxide vehicle or with low, intermediate or high dose of (+)-BPDE were 1, 10, 52 or 514 8-azaguanine-resistant colonies/10(5) survivors, respectively. Independent 8-azaguanine-resistant clones were isolated, and complementary DNAs were prepared by reverse transcription. The coding region of the hypoxanthine (guanine) phosphoribosyltransferase (HPRT) gene was amplified by the polymerase chain reaction and sequenced. Altogether, 368 (+)-BPDE-induced mutant clones were examined. At all doses, base substitutions were the most prevalent mutations observed (about 72% of the mutant clones), followed by exon deletions (about 26% of the mutant clones) and frame-shift mutations (about 6% of the mutant clones). At the high cytotoxic dose, 7 of 120 base substitutions occurred at AT base pairs (6%) and 113 at GC base pairs (94%). At the intermediate noncytotoxic dose, 20 of 82 base substitutions occurred at AT base pairs (24%) and 62 at GC base pairs (76%). At the low noncytotoxic dose, 27 of 76 base substitutions were at AT base pairs (36%) and 49 were at GC base pairs (64%). The results indicated that decreasing the dose of (+)-BPDE decreased the proportion of mutations at GC base pairs and increased the proportion of mutations at AT base pairs. At the dose of (+)-BPDE was decreased, there was a dose-dependent decrease in the proportion of GC-->TA transversions (from 69% to 42% of the base substitutions) and a dose-dependent increase in the proportion of AT-->CG transversions (from 1% to 25% of the base substitutions). The data also indicated dose-dependent differences in (+)-BPDE-induced exon deletions and hot spots for base substitutions at GC and AT base pairs. Although more than 99% of the (+)-BPDE-induced mutations at guanine occurred on the nontranscribed strand of DNA, (+)-BPDE-induced mutations at adenine occurred on both the transcribed and nontranscribed strands. The ratio of mutations at adenine on the transcribed strand to mutations at adenine on the nontranscribed strand was 35:19 in (+)-BPDE-treated V-79 cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Characterization of the allelic differences in the mouse cardiac alpha-myosin heavy chain coding sequence

We have obtained and sequenced the coding sequence of the mouse cardiac alpha-myosin heavy chain (Myhc alpha) from the A/J, BALB/cByJ, C57BL/6J, and DBA/2J inbred mouse strains. Overlapping cDNA sequences were obtained using RNA-PCR and anchor-PCR techniques for these studies. In the A/J mouse strain, the full-length message is 5989 bp long and encodes for a protein consisting of 1938 amino acids (Mr 223,689). The protein deduced sequence of the A/J Myhc alpha was compared with corresponding sequences of human and rat Myhc alpha and beta. These results demonstrated that the mouse Myhc alpha is highly conserved and has maintained the alpha-isoform-specific divergent cluster observed in other Myhc alpha proteins. One difference was the loss of a glutamine at residue 1932, which is due to a change in an RNA splicing site sequence. Allelic variability was observed in both nucleotide and amino acid sequences among the four different inbred mouse strains and generally appears to be random in nature. Three of the nucleotide changes resulted in a different amino acid, while the remaining 46 were silent substitutions.

Chemotactic and mitogenic activities of granulosa cells in developing follicles

Chemotactic and mitogenic activities of granulosa cells in developing follicles were studied. Immature rats were subcutaneously injected with 20 IU of pregnant mare's serum gonadotrophin and killed at various intervals after injection. The ovaries were removed and granulosa cells were isolated and cultured in a serum-free medium supplemented with insulin, transferrin and hydrocortisone. Chemotactic and mitogenic activities in the conditioned medium were determined. Our results demonstrated that in addition to mitogenic activity, chemotactic activity was also expressed in the conditioned medium of granulosa cells. Both activities increased with the maturity of follicles. A gel filtration analysis revealed that there were two peaks showing both mitogenic and chemotactic activities with a molecular size smaller than 5000. These peaks had various sensitivities to heat and trypsin treatment. In addition, the active component of both peaks was organic solvent-extractable. A thin-layer chromatography analysis indicated that the lipid component was not prostaglandin, estradiol or hydrocortisone.

Dose-dependent differences in the profile of mutations induced by an ultimate carcinogen from benzo[a]pyrene

Mutations in the coding region of the hypoxanthine (guanine) phosphoribosyltransferase (HPRT) gene of Chinese hamster V-79 cells were examined after exposure of the cells to a high cytotoxic dose (0.48 microM; 35% survival) and a low noncytotoxic dose (0.04 microM; 100% survival) of the ultimate carcinogen (+)-7R,8S-dihydroxy-9S,10R-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene [(+)-BPDE]. Independent 8-azaguanine-resistant colonies were isolated and cDNAs were prepared by reverse transcription. The coding region of the cDNA of the HPRT gene was amplified by the polymerase chain reaction and sequenced. An examination of the DNA base sequence changes induced by different doses of (+)-BPDE demonstrated that the high dose of (+)-BPDE caused base substitution mutations almost exclusively at G.C base pairs whereas the low dose of (+)-BPDE caused mutations at both G.C and A.T base pairs. Thus, use of a low dose of (+)-BPDE allowed the detection of mutations (at A.T base pairs) that were not readily observed with a high dose of (+)-BPDE. The data also suggest that the low dose of (+)-BPDE may have caused a different profile of base substitutions at G.C base pairs and exon deletions than the high dose. The results indicate dose-dependent differences in the profile of mutations for an ultimate carcinogen.

[The assessment of factor VIII-related antigen in endothelial cells of pulmonary blood vessels in multiple organ failure]

Twenty-five rabbits were randomized into test group (n = 20) and control group (n = 5). Test group animals were fed E coli [(0.4-0.6) x 10(11)/kg] by gastro-lavage and followed by hemorrhagic shock (MBP 40 mmHg for an hour) plus rapid reinfusion with the shed blood. The control group served as operation control. Twelve animals in test group developed MOF (60%). The application of the PAP method in assaying the amount of F VIIIR: Ag in endothelial cells of pulmonary blood vessels. The result showed that the scores of test group was 0.66 +/- 0.24 and the control group 3.01 +/- 0.22. The difference between two groups was statistically significant (P less than 0.05). The PaO2 in MOF animals was 63.1 +/- 9.6 mmHg and the control group 93.6 +/- 4.6 mmHg. The decrease of PaO2 and value scores of FVIIIR: Ag was closely related (r = 0.72, P less than 0.01). The result suggests that a large amount of F VIIIR: Ag was released into blood due to the endothelial injury of pulmonary blood vessels in MOF. The injury of endothelial cells in pulmonary blood vessels was an important factor in pathogenesis of MOF.

Phosphorylation of human interleukin-2 (IL-2)

Human interleukin-2 (IL-2) is a lymphokine which is capable of activating lymphocytes and supporting the long-term in vitro growth of activated T cell clones. Recombinant human IL-2, expressed in either E. coli or cos cells, was shown to be phosphorylated by protein kinase C. Phosphorylated IL-2 synthesized in E. coli was analyzed by SDS-PAGE, reverse phase HPLC, and tryptic peptide mapping. The phosphorylated tryptic peptide was identified as the N-terminal fragment containing a single phosphorylation site at the serine residue at position 7. There was no difference in biological activity between non-phosphorylated and phosphorylated IL-2, as determined by a T cell growth assay. Although the physiological role of phosphorylation of IL-2 is unclear, IL-2 can be labeled with [gamma-32P] ATP and protein kinase C to a high specific radioactivity, and the synthesis of biologically active 32p-labeled IL-2 may be useful for receptor-binding studies of the cells containing low level of phosphoprotein phosphotases.

Use of short DNA oligonucleotides for determination of DNA sequence modifications induced by benzo[a]pyrene diol epoxide

Various organic agents that alkylate DNA are known to induce mutations in bacterial and animal cells. The precise nature and location of modified DNA sequences in such mutants are often difficult to ascertain. In this report, a 10-base-pair oligomer (BamHI linker) is treated with (+/-)-trans-benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide and inserted into replicative form DNA of phage M13 by ligation at a specific restriction site. Escherichia coli are transfected with the recombinant DNA containing the alkylated target, progeny viral plaques are selected, and their DNAs are subjected to DNA sequence analysis at the region of oligomer insertion. For the alkylated inserts used in this study, the DNA sequence analysis of progeny viral DNA showed that nucleotide deletions were present in every clone examined. These deletions occurred primarily, but not exclusively, at G-C cluster regions, varied from 1 to 24 base pairs in length, and included both target and nontarget nucleotides. A second type of repair, which restores most of the original nucleotide bases in the alkylated insert, is also implied by the DNA sequence data obtained.