Influence of incomplete neoadjuvant chemotherapy on esophageal carcinoma.

BACKGROUND: Neoadjuvant chemotherapy (NAC) involving two cycles of cisplatin plus fluorouracil is recommended in Japan as a standard treatment for resectable, locally advanced esophageal squamous cell carcinoma (ESCC). We have encountered patients who were administered incomplete chemotherapy because of adverse events or the patient's refusal of treatment. Here, we retrospectively investigated the influence on perioperative outcomes and long-term prognosis of patients with ESCC who underwent complete (two cycles) or incomplete (one cycle) NAC. METHODS: We retrospectively investigated 133 patients with locally advanced ESCC of the thoracic esophagus who underwent NAC. We compared the perioperative results and prognoses of patients who underwent complete or incomplete NAC because of adverse events or the patient's refusal of treatment. RESULTS: Of 133 patients, 37 patients did not receive the second cycle of NAC; the remaining 96 patients received the second cycle of NAC as scheduled. There were no significant differences in the clinical backgrounds, surgical results, or operative morbidity rates between the groups. Patients in both groups were similarly administered postoperative chemotherapy regimens. There was no significant difference in disease-free survival or overall survival. CONCLUSIONS: We suggest that perioperative outcomes and long-term prognosis of patients with locally advanced ESCC were not significantly influenced, even if the patients did not receive a complete cycle of NAC. When certain adverse events occur after the first cycle of NAC, we believe that it is nevertheless possible to discontinue chemotherapy.

Altered social interactions in male juvenile cynomolgus monkeys prenatally exposed to bisphenol A.

Bisphenol A (BPA) is a widespread environmental contaminant, and humans are routinely exposed to BPA. We investigated whether prenatal exposure to BPA influences behavioral development in juvenile cynomolgus monkeys (Macaca fascicularis). Pregnant cynomolgus monkeys were implanted with subcutaneous pumps and exposed to 10µg/kg/day BPA or vehicle (control) from gestational day 20 to 132. Both BPA-exposed and control juvenile monkeys (aged 1-2years) were assessed using the peer-encounter test that was conducted to evaluate behaviors in social interaction with a same-sex, same-treatment peer. In the encounter test, prenatal BPA exposure significantly reduced environmental exploration and presenting, a gesture related to sexual reproduction, and increased visual exploration, but only in males; furthermore, it significantly reduced the typical sexual dimorphism of the aforementioned behaviors normally observed between male and female juvenile cynomolgus monkeys. This study demonstrates that prenatal BPA exposure affects behavioral development during adolescence and results in the demasculinization of key sexually dimorphic behaviors in male juvenile monkeys.

Differentiation of neural cells in the fetal cerebral cortex of cynomolgus monkeys (Macaca fascicularis).

Proliferation and programmed cell death are important in the formation of morphologic structures and functional activity during CNS development. We used immunohistochemical and TUNEL methods to examine the proliferation and differentiation of neural cells in, distribution of apoptotic cells in, and microglial cell involvement in the removal of apoptotic cells from the fetal cerebral cortex of cynomolgus monkeys. At embryonic day (E) 50 and E80, the neuroepithelium contained many mitotic cells. Cells staining for PCNA (a nuclear marker of proliferating cells) were prominent in the proliferative zone, whereas cells positive for NeuN (a neuron-specific marker) were absent. GFAP staining for glial cells was positive in the neuroepithelium and radial glial fibers. Iba1-positive cells (that is, macrophages and microglia) were distributed throughout all regions at all time points but accumulated especially in the ventricular zone at E80. Apoptotic morphology (at E80) and TUNEL-positive cells (that is, containing DNA fragmentation; at E50 and E80) were observed also. At E120 and E150, most PCNA-positive cells were in the ventricular zone, and NeuN-positive cells were prominent in all layers except layer I-II at E120. GFAP immunoreactivity was detected mainly in cells with fine processes in the white matter. Neither apoptosis nor TUNEL-positive cells were detected at either E120 or E150. These results suggest that proliferation, migration, and neural cell death occur during midgestation (that is, E50 to E80) in fetal brain of cynomolgus macaques, whereas differentiation and maturation of neural cells occur after midgestation (E80).

Maternal plasma polychlorinated biphenyl levels in cynomolgus monkeys (Macaca fascicularis) affect infant social skills in mother-infant interaction.

Polychlorinated biphenyls (PCBs) are endocrine disrupting chemicals that disturb normal development of embryonic brains. In the present study, we evaluated the relationship between maternal plasma PCB concentration and infant behavioral characteristics in mother-infant interactions. We grouped 20 pregnant cynomolgus monkeys (Macaca fascicularis) into higher and lower PCB exposure groups; monkeys in the higher PCB group had PCB concentrations above 15 pg/g, which is representative of natural exposure levels. Maternal PCB concentration correlated negatively with infant behaviors (approach, look, proximity, locomotion) at the age of 6 months (p < .05), when an increase in these behaviors should normally occur. These results suggest that maternal PCB exposure may affect the development of infant social behavior in cynomolgus monkeys. Furthermore, this study provides primate evidence to support observations of associations between behavioral and learning disabilities and prenatal exposure to PCBs in humans.

Fetal and neonatal goiter in cynomolgus monkeys following administration of the antithyroid drug thiamazole at high doses to dams during pregnancy.

To evaluate morphologic alterations in the thyroid gland in the second generation in cynomolgus monkeys, pregnant dams were exposed to high doses of thiamazole. In Experiment A, dams received thiamazole intragastrically via a nasogastric catheter from gestation day (GD) 50 to GD 150 or on the day before delivery. Initially, the dose level was 20 mg/kg/day (10 mg/kg twice daily); however, the dose level was subsequently decreased to 5 mg/kg/day (2.5 mg/kg twice daily), since deteriorated general conditions were observed in two dams. Six out of seven neonates died on the day of birth. The cause of neonatal death was tracheal compression and suffocation from goiter. The transplacental exposure to thiamazole affected the fetal thyroid glands and induced goiter in all neonates. The surviving neonate was necropsied 767 days after discontinuation of thiamazole exposure and showed reversibility of the induced changes. In Experiment B, dams were intragastrically administered thiamazole at 5 mg/kg/day (2.5 mg/kg twice daily) for treatment periods from GDs 51 to 70, 71 to 90, 91 to 110, 111 to 130 and 131 to 150. All fetuses showed enlarged thyroid glands but were viable. Histopathologically, hypertrophy and/or hyperplastic appearance of the follicular epithelium of the thyroid gland was observed at the end of each treatment period. The most active appearance of the follicular epithelium, consisting of crowded pedunculated structure, was demonstrated at end of the treatment period from GD 131 to 150. This is the first report on the morphology of fetal and neonatal goiter in the cynomolgus monkey.

Fetal malformations and early embryonic gene expression response in cynomolgus monkeys maternally exposed to thalidomide.

The present study was performed to determine experimental conditions for thalidomide induction of fetal malformations and to understand the molecular mechanisms underlying thalidomide teratogenicity in cynomolgus monkeys. Cynomolgus monkeys were orally administered thalidomide at 15 or 20mg/kg-d on days 26-28 of gestation, and fetuses were examined on day 100-102 of gestation. Limb defects such as micromelia/amelia, paw/foot hyperflexion, polydactyly, syndactyly, and brachydactyly were observed in seven of eight fetuses. Cynomolgus monkeys were orally administered thalidomide at 20mg/kg on day 26 of gestation, and whole embryos were removed from the dams 6h after administration. Three embryos each were obtained from the thalidomide-treated and control groups. Total RNA was isolated from individual embryos, amplified to biotinylated cRNA and hybridized to a custom Non-Human Primate (NHP) GeneChip((R)) Array. Altered genes were clustered into genes that were up-regulated (1281 genes) and down-regulated (1081 genes) in thalidomide-exposed embryos. Functional annotation by Gene Ontology (GO) categories revealed up-regulation of actin cytoskeletal remodeling and insulin signaling, and down-regulation of pathways for vasculature development and the inflammatory response. These findings show that thalidomide exposure perturbs a general program of morphoregulatory processes in the monkey embryo. Bioinformatics analysis of the embryonic transcriptome following maternal thalidomide exposure has now identified many key pathways implicated in thalidomide embryopathy, and has also revealed some novel processes that can help unravel the mechanism of this important developmental phenotype.

In utero and lactational exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces a reduction in epididymal and ejaculated sperm number in rhesus monkeys.

A long-term developmental toxicity study of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure was performed in rhesus monkeys and the effect on male reproductive organs was determined in the second generation. Dams received 0, 30 or 300 ng/kg TCDD subcutaneously on Day 20 of gestation, and then 5% of the initial dose was injected every 30 days until Day 90 after delivery. The offspring were maintained until reaching sexual maturity, and evaluated by semen analysis, and histopathology of the testes and epididymides. Ejaculated sperm concentration was severely reduced at 300 ng/kg, and sperm viability and activity were dose-proportionally reduced, although effects on spermatogenesis were slight. Histomorphometry revealed markedly reduced area of the ductus epididymis accompanying decreased reserved sperm in the 30 and 300 ng/kg groups. In conclusion, in utero and lactational exposure to TCDD induced a reduction of sperm quality in rhesus monkeys.

Developmental toxicity of dibutyltin dichloride given on three consecutive days during organogenesis in cynomolgus monkeys.

We previously reported that the administration of dibutyltin dichloride (DBTCl) by nasogastric intubation during the entire period of organogenesis, days 20-50 of pregnancy, was embryolethal, but not teratogenic, in cynomolgus monkeys. The present study was conducted to further evaluate the developmental toxicity of DBTCl given to pregnant monkeys on 3 consecutive days during organogenesis. Cynomolgus monkeys were given DBTCl at 7.5 mg/kg body weight/day by nasogastric intubation on days 19-21, 21-23, 24-26, 26-28, 29-31, 31-33, or 34-36 of pregnancy, and the pregnancy outcome was determined on day 100 of pregnancy. Embryonic/fetal loss was observed in 1 female given DBTCl on days 19-21, 2 females given DBTCl on days 24-26, and 1 female given DBTCl on days 34-36. There were no effects of DBTCl on developmental parameters in surviving fetuses, including fetal body weight, crown-rump length, tail length, or placental weight. No external, internal, or skeletal malformations were detected in fetuses in any group. DBTCl did not affect the incidence of fetuses with skeletal variation or skeletal ossification of fetuses. These data confirm our previous findings that DBTCl was embryolethal, but not teratogenic, in cynomolgus monkeys.

Alterations in male infant behaviors towards its mother by prenatal exposure to bisphenol A in cynomolgus monkeys (Macaca fascicularis) during early suckling period.

Bisphenol A (BPA) is an environmental chemical with physiological potencies that cause adverse effects, even at environmentally relevant exposures, on the basis of a number of studies in experimental rodents. Thus, there is an increasing concern about environmental exposure of humans to BPA. In the present study, we used experimentally controlled cynomolgus monkeys (Macaca fascicularis) to assess the influence of prenatal exposure to BPA (10 microg/(kg day)) via subcutaneously implanted pumps and examined social behaviors between infants and their mothers during the suckling period. Mother-infant interactions in cynomolgus monkeys had behavioral sexual dimorphism associated with sex of infant from early suckling period. Prenatal exposure to BPA altered the behaviors of male infants significantly; BPA-exposed male infants behaved as female infants. And it also affected some of female infant behaviors. Consequently, gestational BPA exposure altered some behaviors of their mothers, mainly in male-nursing mothers. These results suggest that BPA exposure affects behavioral sexual differentiation in male monkeys, which promotes the understanding of risk of BPA exposure in human.

In utero and lactational exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) affects bone tissue in rhesus monkeys.

Bone tissue is one of the target tissues for dioxins and dioxin-like compounds. Therefore, the aim of this study was to investigate effects of in utero and lactational exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), on bone tissue in rhesus monkey, the most human-like experimental model available. Pregnant rhesus monkeys (Macaca mulatta; age 4-10 years) were exposed to TCDD with a total dose of 40.5-42.0 or 405-420ng/kg bodyweight by repeated subcutaneous injections starting at gestational day 20 and followed by injections every 30 days until 90 days after delivery. At a mean age of 7 years the offspring were sacrificed and the femur bone dissected. Results from peripheral Quantitative Computed Tomography (pQCT) analyses of the metaphyseal part of the femur bones in female offspring showed significant increases in trabecular bone mineral content (BMC; +84.6%, p<0.05, F-value (F)=5.9) in the low-dose treatment group compared with the controls. In the same animals, analysis of the mid-diaphyseal part revealed increases in total BMC (+21.3%, p<0.05, F=5.2) and cortical cross-sectional area (CSA; +16.4%, p<0.01, F=7.4) compared with the controls. In males, changes in biomechanical properties indicating more fragile bone were observed. Displacement at failure were significantly increased in the male low-dose group compared to the controls (+38.0%, p<0.05, F=11). The high dose of TCDD did not induce any significant changes in bone morphology. In conclusion, in utero and lactational low-dose, but not high-dose exposure to 2,3,7,8-TCDD induced disruption of bone tissue development in rhesus monkey, a result suggesting that similar effects might occur in humans also.

Developmental toxicity of dibutyltin dichloride in cynomolgus monkeys.

Dibutyltin dichloride (DBTCl) has been shown to be teratogenic in rats. The present study was conducted to determine the teratogenic potential of DBTCl given to pregnant monkeys during the entire period of organogenesis. Cynomolgus monkeys were dosed once daily by nasogastric intubation with DBTCl at 0, 2.5 or 3.8 mg/kg on days 20-50 of pregnancy, the whole period of organogenesis. The pregnancy outcome was determined on day 100 of pregnancy. In both DBTCl-treated groups, a significant increase in the incidence of pregnant females with soft stool and/or diarrhea, and with yellowish stool was observed. Maternal body weight gain at 3.8 mg/kg and food consumption at 2.5 and 3.8 mg/kg were decreased during the administration period. The survival rate of fetuses at terminal cesarean sectioning was decreased in the DBTCl-treated groups and significantly decreased at 2.5 mg/kg. There were no changes in the developmental parameters of surviving fetuses, including fetal body weight, crown-rump length, tail length, sex ratio, anogenital distance and placental weight, in the DBTCl-treated groups. No external, internal or skeletal malformations were found in the fetuses in any group. Although internal and skeletal variations were found, no difference in the incidence of fetal variation was noted between the control and DBTCl-treated groups. No effect on skeletal ossification was observed in fetuses in the DBTCl-treated groups. The data demonstrate that DBTCl is embryolethal but not teratogenic in cynomolgus monkeys.

[A case of advanced rectal cancer responding to l-Leucovorin (LV)/5-fluorouracil( 5-FU) therapy as neoadjuvant chemotherapy].

We report a case in which l-Leucovorin/5-fluorouracil (l-LV/5-FU) therapy was remarkably effective for advanced rectal cancer as neoadjuvant chemotherapy (NAC). A 54-year-old man complained of bloody stool and constipation,and was diagnosed as having stage IIIB advanced rectal cancer with N2 lymphnode metastases on July 31, 2003. Two cycles of NAC by l-LV/5-FU therapy were performed. On abdominal computed tomography (micro CT), the primary lesion in the rectum decreased 82% and the metastatic lymphnodes had disappeared. As we established a diagnosis of the downstaging for stage II, a lower anterior resection with D3 lymphnode dissection was performed on December 5, 2003. The pathological examination demonstrated II, mod, 1.8 x 2.2 cm, a1, ly1,v0, ow(-), aw(-), n0, stage II. We could allow curability-A resection. The pathological effect of chemotherapy was grade 2 in which cancer cells became necrotic, suggesting apoptosis. The postoperative course was good. Postoperatively, 3 cycles of l-LV/5-FU therapy were performed. Although the patient had to be followed with internal use of 5-FU 200 mg/day as an outpatient from June 2, 2004, to date, there has been no sign of recurrence during the 12-month follow-up after the operation. Moreover, no adverse by chemotherapy was seen during the treatment. Thus, NAC by this therapy may be useful for patients with advanced rectal cancer.

[A case of advanced gastric cancer with direct invasion of the transverse colon responding to paclitaxel/5'-DFUR combined therapy].

A 50-year-old man was diagnosed with non-resectable scirrhous gastric cancer of antrum accompanied with colon ileus due to direct invasion of the transverse colon. As the ileus improved after cecostomy, chemotherapy with TS-1/cisplatin(CDDP) was performed. Because of no response, 4 cycles of paclitaxel (PTX)/doxifluridine (5'-DFUR) therapy was performed as second-line chemotherapy. Since the stenosis of transverse colon dilated completely and the tumor disappeared, we performed total gastrectomy and right hemicolectomy, and could resect completely. Though 2 cycles of PTX/5'-DFUR therapy was performed postoperatively and the patient's postoperative condition was good, he was suffering from carcinomatous peritonitis complicated by ileus and obstructive jaundice 4 months after operation. He died 1 year after the first medical examination, but his QOL was fairly good for 10 months. PTX/5'-DFUR therapy, which has only slight complications, may be useful for patients with recurrent gastric cancer who had been treated with 5-FU administration as first-line chemotherapy. But the future problem was how to control dissemination after surgery in a resectable case after chemotherapy.

[A case of cecal cancer with multiple liver metastases responding to irinotecan (CPT-11)/cisplatin (CDDP) combination therapy for elevation of CA19-9 after complete response (CR) by l-leucovorin(LV)/5-fluorouracil(5-FU) therapy].

A 62-year-old woman complained of abdominal pain and diarrhea from February 2, 2002. She was diagnosed with advanced cecal cancer with simultaneous multiple liver metastases. The serum level of CA 19-9 was 420 U/ ml. Ileoceal resection with D3 lymphnode dissection. The replacement of reservoir for hepatic arterial infusion (HAI) was performed on February 2, 2002. As the dissemination was seen near the mesocolon at laparotomy, we could resect all together. Pathological examination demonstrated II, 5.0 x 2.5 cm, mod, se, INFgamma, ly(1), v(1), n(2), stage IV. Systemic l-leucovorin/5-fluorouracil (l-LV/5-FU) + HAI of weekly high-dose 5-FU combination therapy was initiated at postoperative 14 days. The serum CA 19-9 level decreased immediately but was not within the normal range. On abdominal computed tomography (CT), liver metastatic lesions decreased 9 9% on May 27, 2002 and disappeared on August 26, 2002. Though there were no signs of recurrence, the serum CA 19-9 level elevated as of October, 2002. Since the hepatic artery was occluded, HAI was discontinued on November 28, 2002. The serum CA 19-9 level elevated inspite of the continuation of the l-LV/5-FU therapy which we increased an amount of 5- FU. Thus, we changed low-dose irinotecan (CPT-11)/cisplatin (CDDP) therapy. The serum level of CA 19-9 decreased gradually and got with in normal range on March, 2004. It did not elevate since then. Low-dose CPT-11/CDDP therapy may be useful for patients with advanced colon cancer thought to be resistant to 5-FU as second-line chemotherapy.

In utero and lactational exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) affects tooth development in rhesus monkeys.

We thought to validate the current tolerable daily intake (TDI) value for dioxin (4 pg/kg) in Japan. Pregnant rhesus monkeys received an initial dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; 0, 30, or 300 ng/kg subcutaneously) on day 20 of gestation; the dams received additional injection of 5% of the initial dose every 30 days until day 90 after delivery. The teeth of stillborn, postnatally dead, and surviving offspring (now approximately 4 years old) were evaluated. None of the offspring in the 0 and 30 ng/kg groups (n=17 and 15, respectively) had tooth abnormalities, whereas 10 of 17 in the 300 ng/kg had them. These findings suggest the lowest-observed adverse-effect level (LOAEL) for TCDD in the rhesus monkey is between 30 and 300 ng/kg, and probably is close to that for rodents (86 ng/kg) on which the current TDI was based. It is reasonable to conclude that the current TDI needs no immediate modification.

[A case of recurrent stomach cancer treated with 5-fluorouracil responding to weekly paclitaxel therapy].

We report a patient with unresectable stage IV stomach cancer with metastasis to the paraaortic lymph nodes who achieved an effective response to neoajuvant chemotherapy, which allowed curability-B resection, and in whom weekly paclitaxel (TXL) therapy for postoperative recurrence was very effective in improving QOL. The patient was a 65-year-old man. After preoperative PMFE therapy, CEA decreased from 68.1 ng/ml to 0.8 ng/ml, and CA19-9 from 15,000 U/ml to 190 U/ml. The paraaortic lymph nodes disappeared, and stomach wall thickening decreased. The overall response to treatment was evaluated as a partial response (PR). After surgery, the patient was given TS-1, but became unable to take oral medication because of retroperitoneal and lymph node recurrence. Since the cancer appeared to be resistant to 5-fluorouracil (5-FU), the patient was treated by weekly TXL therapy. Increased appetite and weight gain were observed from the middle of the first course of therapy, and CEA decreased from 28.2 ng/ml to 4.9 ng/ml, and CA19-9 from 15,000 U/ml to 2,000 U/ml. Abdominal CT scans demonstrated shrinkage of the tumor. Although the patient died 1 year and 8 months after the initial examination, he was able to take oral medication and maintain good QOL for 10 months after the start of TXL therapy. Only grade 1 side effects (alopecia and leukopenia) were observed throughout the course. These results suggest that TXL therapy is effective also for 5-FU-resistant stomach cancer, and exhibits effects early even in patients in a poor general condition, causing only mild side effects, with early improvements in QOL.

[A case of advanced descending colon cancer with peritoneal dissemination responding to weekly high-dose l-leucovorin/5-fluorouracil combination therapy].

We report a case in which l-leucovorin/5-fluorouracil (l-LV/5-FU) combination therapy was remarkably effective for non-resectable advanced descending colon cancer with carcinomatous peritonitis. A 65-year-old man complained of severe abdominal distension, abdominal pain and pulmonary failure, and was diagnosed as having ileus due to descending colon cancer. The patient underwent urgent open laparotomy to release the ileus condition on March 5, 2002. During the laparotomy, we established a diagnosis of nonresectable descending colon cancer accompanied by severe peritoneal dissemination and therefore performed only double-barreled transverse colostomy. The postoperative course was very good. Pathological examination of omental dissemination demonstrated moderately differentiated adenocarcinoma and cytology of ascites was class II. The levels of serum CEA and CA19-9 were within the normal ranges. l-LV/5-FU therapy was initiated postoperatively. Seven cycles of this chemotherapy regimen was performed with no apparent side effect during the treatment. There was no postoperative accumulation of carcinomatous ascites. The patient gained 15 kg compared with body weight admission. On abdominal computed tomography (CT), the primary lesion of the colon decreased 98% and there was no ascites found. To date, there has not been any sign of recurrence during the 19 months of follow-up after this therapy, and we are currently discussing closure of the transverse colostomy. This therapy may be useful for patients with advanced colon cancer accompanied by peritoneal dissemination.