[Analysis of the efficacy and safety of pulsed radiofrequency for the treatment of thoracic postherpetic neuralgia in elderly patients with different pain phenotypes].

Objective: To analyze the efficacy and safety of pulsed radiofrequency (PRF) for the treatment of thoracic postherpetic neuralgia (PHN) in elderly patients with different pain phenotypes. Methods: A total of 201 elderly thoracic PHN patients, including 110 males and 91 females aged (72.2±6.9) years who received high-voltage, long-duration PRF at the dorsal root ganglion at Nanjing Drum Tower Hospital Clinical College of Nanjing University of Chinese Medicine from January 2020 to December 2022, were retrospectively included. The neuropathic pain symptom inventory (NPSI) was used to evaluate the five different pain phenotypes, which included superficial spontaneous pain, deep spontaneous pain, paroxysmal pain, evoked pain, and paresthesia/dysesthesia, and to analyze the distribution of the five pain phenotypes. The numerical rating scale (NRS) and NPSI scores of all patients were compared before treatment and three months after treatment to evaluate the efficacy and safety of PRF for different pain phenotypes and pain phenotype combinations. Results: All patients had two or more pain phenotypes, and 50.2% (101/201) of the patients had five pain phenotypes at the same time. Compared with those before treatment, three months after treatment, the NPSI scores for superficial spontaneous pain, deep spontaneous pain, paroxysmal pain, evoked pain and paresthesia/dysesthesia decreased (all P<0.05), and the scores decreased byï¼»M（Q1，Q3）］3.0 (2.0, 4.0), 1.5 (0.5, 2.5), 3.0 (2.5, 4.0), 2.3 (1.0, 4.0), and 1.0 (0.5, 2.0) points, respectively, the differences were statistically significant (P<0.001). The decrease in the NPSI score in patients with paroxysmal pain was greater than that in patients with the other 4 pain phenotypes (all P<0.05). After treatment, the NRS score decreased by 4.0 (3.0, 5.0), 4.0 (3.0, 5.0), 4.0 (3.0, 5.0) and 5.0 (4.0, 6.0) points in patients with 2, 3, 4 and 5 pain phenotypes, respectively, and the difference was statistically significant (P<0.001). The decrease in the NRS score was greater in patients with a combination of 5 pain phenotypes than that in patients with a combination of 3 and 4 pain phenotypes (all P<0.05). No complications, such as pneumothorax, haematoma or infection, occurred in any of the patients during treatment. Conclusion: PRF has different therapeutic effects on PHN patients with different pain phenotypes, it has the best effect on paroxysmal pain, and the treatment is safe.

[Efficacy and safety of modified Hartel approach in the treatment of primary trigeminal neuralgia with radiofrequency thermocoagulation].

Objective: To assess the efficacy and safety of modified Hartel approach in the treatment of primary trigeminal neuralgia with radiofrequency thermocoagulation. Methods: A total of 89 patients with primary trigeminal neuralgia in Nanjing Drum Tower Clinical College of Xuzhou Medical University from July 2021 to July 2022 were prospectively included, and were divided into experimental group (n=45, modified Hartel approach: selecting 2.0 cm lateral to and 1.0 cm below angulus oris as insertion point) and control group (n=44, traditional Hartel approach: selecting 2.5 cm lateral to the angulus oris as insertion point) according to the random number table method. There were 19 males and 26 females in the experimental group, and aged (67.6±8.8) years. Meanwhile, there were 19 males and 25 females in the control group, and aged (64.8±11.7) years. All the patients were treated by CT-guided radiofrequency thermocoagulation. The success rate of one-time puncture, number of punctures, the time of puncture, operation time, numerical rating scale (NRS) scores and complications were recorded and compared between the two groups. Results: The success rate of one-time puncture in experimental group was 64.4% (29/45), which was higher than that in control group 31.8% (14/44) (P<0.05). The number of punctures [M (Q1, Q3)], the time of puncture [M (Q1, Q3)] and operation time in the experimental group were 1 (1, 2), 218 (206, 378) s, (19.9±2.7) min, which were less than those of control group [2 (1, 3), 390 (231, 598) s, (27.0±3.9) min] (all P<0.05). The NRS scores [M (Q1, Q3)] of 1 day, 1 month and 3 months after surgery in the experimental group were 1 (1, 2), 1 (0, 2) and 1(0, 1), respectively, which were lower than the baseline level [6 (6, 7)] (all P<0.05). The NRS scores [M (Q1, Q3)] of 1 day, 1 month and 3 months after surgery in the control group were 1 (1, 2), 1 (0, 2) and 1 (0, 2), respectively, which were lower than the baseline level [6 (6, 7)] (all P<0.05). There was no statistically significant difference in the incidence of nausea and vomiting, facial numbness, and decreased masticatory muscle strength between the two groups (all P>0.05) In the experimental group, two patients had puncture needles into the oral cavity, with timely detection and replacement of puncture needles, and no infection occurred. There was no cerebrospinal fluid leakage and decreased corneal reflex in both groups. Conclusion: The modified Hartel approach can significantly improve the success rate of one-time puncture via foramen ovale, reduce the operation time and the incidence of postoperative facial swelling, which is a safe and effective puncture method.

[Singleton placentas with abnormal shape: a clinicopathological analysis of 130 cases].

Objective: To investigate the pathological characteristics of singleton placenta with abnormal shape and its influence on the outcome of maternal-fetal pregnancy. Methods: The clinicopathological data of singleton placentas with abnormal shape from January 2014 to December 2020 in the Department of Pathology, Haidian Maternal and Children Health Hospital were analyzed retrospectively. Results: There were 130 singleton placentas with abnormal shape in this cohort, including 48 succenturiate placentas, 12 bilobed placentas, 50 marginate placentas, 13 circumvallate placentas, 3 annular placentas, 2 membranous placentas and 2 fenestrated placentas. Gestational age ranged from 29+5 to 40+4 weeks. There were 51 cases of premature rupture of membranes, 11 cases of placenta previa, 5 cases of placental abruption, 15 cases of placental adhesion/implantation and 27 cases of postpartum hemorrhage. There were 46 preterm fetuses,28 fetuses with fetal growth restriction, 22 fetuses with intrauterine distress, and 1 fetus with intrauterine death. Grossly, the placental lobules of succenturiate placentas had apparent size difference, while two lobules of bilobate placenta were more consistent. The chorionic plate size was smaller than the bottom plate of circumvallate placenta, the folded fetal membrane in the rim of placenta was thickened (termed marginate placenta if there was no thickening). The membranous placenta was characterized by a thin, large membrane-like shape. Annular placenta showed characteristic hollow cylinder, ring or horseshoe-shape. Fenestrated placenta was characterized by tissue defects near central area. Microscopically, functional/morphologic changes were the main manifestations of inadequate maternal-fetal perfusion, including villous infarction, distal villous dysplasia and excessive villous maturation. Conclusions: The abnormal shaped singleton placentas showed variable extent of inadequate maternal-fetal perfusion, which may lead to adverse pregnancy outcomes such as premature delivery, fetal growth restriction, intrauterine distress or fetal death.

[Autopsies and placental examinations of perinatal fetal deaths: a clinicopathological analysis of 105 cases].

Objective: To summarize the clinicopathological factors related to perinatal fetal death and to evaluate importance of fetal autopsy and placental pathology. Methods: The clinicopathological data of 105 perinatal fetal deaths in Beijing Haidian Maternal and Child Health Hospital from November 2012 to December 2020 were retrospectively analyzed. Relevant literature was also reviewed. Results: The maternal age of the deceased fetuses ranged from 22 to 43 years with the average (31.35±4.04 years), and the gestational weeks were 28-40+6 weeks. Among them, 101 were singleton cases and 4 twin cases. 103 fetuses died in uterus and 2 died during delivery. Relevant factors analysis of the 105 perinatal fetal deaths showed that 86 cases (81.9%, 86/105) were related to umbilical cord/placental abnormality, 10 cases (9.5%, 10/105) uterine infection, 6 cases (5.7%, 6/105) fetal factors, 1 case was fetal maternal blood transfusion syndrome, 1 case twin blood transfusion syndrome, and 1 case died of complete uterine rupture. Among the 86 cases related to umbilical cord/placental abnormality, the diagnosis was most often based on the gross examination of placenta. The most common cause of death was umbilical cord torsion with thin root, followed by placental abruption, tight umbilical cord winding, vascular rupture and umbilical cord true knot. The morphology of placenta revealed mainly functional changes. Among the 10 cases related to intrauterine infections, the placenta generally showed lobular placental edema. The morphological characteristics of ascending infection were mainly acute chorioamnionitis, and the morphological characteristics of blood-borne infection were mainly acute or chronic villitis, as well as villous interstitial inflammation. Identification of viral inclusions suggested viral etiology, while the final diagnosis was relied on laboratory testing. Among the 6 cases related to fetal abnormality, the diagnostic value of placenta was limited and the diagnosis could be made with fetal autopsy. Conclusion: The causes of perinatal fetal death are complex, diverse, and often the synergistic result of multiple factors. Fetal autopsy and placental pathology are the key technical means to identify the cause of death and deserve more attention and utilization.

[Application of 3D-printed navigation plate in pulsed radiofrequency therapy of dorsal root ganglion in thoracic postherpetic neuralgia].

Objective: To evaluate the accuracy, efficacy and safety of 3D-printed personalized navigation template in the treatment of thoracic postherpetic neuralgia (PHN) with dorsal root ganglion pulsed radiofrequency (DRG-PRF). Methods: A total of 63 patients with thoracic PHN from March 2019 to December 2020 in Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School were enrolled and randomly divided into study group (n=31) and control group (n=32) by random number table method. The study group received DRG-PRF treatment assisted by 3D-printed navigation template, while the control group received DRG-PRF treatment guided by conventional CT. The one-time success rate of puncture, the incidence of puncture times ≥3, the number of punctures, puncture time, visual analogue scale (VAS) score and surgical complications between the two groups were compared. Results: The one-time success rate of puncture in study group was 84.9% (79/93), which was higher than that of control group [30.2% (29/96)] (P<0.001). The incidence of puncture times ≥3, the number of punctures, puncture time in study group were 4.3% (4/93), 1 (1, 1) and 2.9 (2.8, 3.0) min, respectively, which were lower than that of the control group [21.9% (21/96), 2(1, 3), 9.0 (4.5, 12.9) min, respectively] (all P<0.01). No difference was found in VAS score at each time point before and after surgery between the two groups (all P>0.05). There was one case of pleura puncture in the control group, but no other complications such as straying into vertebral canal, hematoma, spinal cord injury, limb movement disorder, infection were found in the two groups. Conclusions: 3D-printed personalized navigation template is an effective method to guide DRG-PRF for the treatment of thoracic postherpetic neuralgia. It can significantly improve the surgical efficiency of DRG-PRF, but has no significant effect on the surgical efficacy.

[Study of portal venous pressure gradient to predict high-hepatic encephalopathy-risk population post TIPS].

Transjugular intrahepatic portosystemic shunt (TIPS) can effectively reduce the portal venous pressure and relieve the clinical complications related to portal hypertension. However, hepatic encephalopathy (HE) is still the main complication post TIPS. Studies have shown that patients over 65 years old with liver function reserve in Child-Pugh grade C are the high-HE-risk group post TIPS, and early TIPS treatment can benefit the survival of these high-risk patients. In this study, TIPS was used to treat 60 cases aged > 65 years old and liver function reserve in Child-Pugh grade C (decompensated liver cirrhosis) with esophagogastric variceal bleeding. The clinical results of 1-year was observed and the porto systemic gradient (PSG) was evaluated. The relationship between the incidence of HE and the PSG of patients with and without HE were compared to evaluate the effect of PSG on the incidence of HE.

A novel HLA-DRB1 allele, DRB1*16:36 identified in a Chinese individual from the Xinjiang region.

A novel class II human leukocyte antigen allele HLA-DRB1*16:36 is described.

Independent and joint effects of the IL-6 and IL-10 gene polymorphisms in pulmonary tuberculosis among the Chinese Han population.

We investigated the association between interleukin (IL)-6 and IL-10 gene polymorphisms and the susceptibility to pulmonary tuberculosis (PTB). DNA samples were obtained from 191 Han Chinese patients with PTB and 191 healthy control subjects. IL-6 (-572, -174, -597) and IL-10 (-1082, -819) polymorphisms were analyzed using polymerase chain reaction-restriction fragment length polymorphism. The IL-6 -572 C/C and IL-10 -819 T/T genotypes were observed less frequently in the case group than in the control group, with crude odds ratios of 0.591 [95% confidence interval (CI) = 0.381-0.917] and 0.401 (95%CI = 0.257-0.627), respectively. A significant association remained after adjusting for environmental factors in multivariate logistic analysis. The homozygote genotypes of IL-6 -572 and IL-10 -819 had an adjusted OR of 0.565 (95%CI = 0.356-0.898) and 0.341 (95%CI = 0.210-0.553), respectively. These results indicate that the mutant heterozygote IL-10 -1082 A/ G+G/G genotype and the homozygote IL-10 -819 T/T genotype have a combined effect on PTB. These results suggest that the IL-6 -572 C/C and IL-10 -819 T/T genotype polymorphisms are protective factors against PTB.

[Analysis of clinical features and surgical outcomes of petrous bone cholesteatomas].

Objective: To analyze the clinical features and surgical outcomes of petrous bone cholesteatomas (PBCs). Methods: Data from 39 PBCs patients treated in the Department of Otorhinolaryngology, Xijing Hospital from September 2011 to December 2017 were reviewed retrospectively, including 23 males, 16 femals, aged 12-71 years old, with the median age of 37. Clinical classifications, surgical methods, facial and hearing function, and intraoperative and postoperative complications were made summary analysis. Results: In this study, five patients were congenital PBCs and 34 patients were acquired PBCs. The common clinical symptoms were hearing loss (100%, 39/39), ear discharge/pus (89.7%, 35/39) and facial paralysis (46.2%, 18/39). According to Sanna's classification, 14 cases were supralabyrinthine, including three cases underwent transcochlear (TC) approach, six cases underwent transotic (TO) approach and five underwent translabyrinthine (TL) approach. 10 cases were infralabyrinthine, including eight cases underwent subtotal petrosectomy, one case underwent TO approach and one underwent TL approach.10 cases were massive, including seven cases underwent TC approach, three cases underwent TO approach. Five cases were infralabyrinthine-apical, including two cases underwent TC approach, two cases underwent TO approach, and one case underwent endoscope assisted infratemporal fossa type B. The degree of facial nerve (FN) dysfunction from high to low was massive (6/10), supralabyrinthine (8/14), infralabyrinthine-apical (2/5) and infralabyrinthine (2/10). 19 cases involved in facial nerve operation, three cases underwent FN decompression, four cases underwent FN rerouting, four cases underwent nerve grafting, and one case underwent facial-hypoglossal anastomosis. Preoperative FN involvement in 18 cases, and the FN function was improved in 14 cases after surgery. The improved rate of postoperative FN function was 77.8%. The bone conducted hearing retained 50.0% (14/28) postoperatively. Five cases with cerebrospinal fluid leak were managed by inserting free muscle plugs and cavity obliteration. Two cases with the cholesteatomas matrix involved the sigmoid sinus and the jugular bulb, and occlusion of the sigmoid sinus was performed. Postoperatively, two patients presented with synkinesis. The patients were followed up for 40 to 115 months, and there was no recurrence. Conclusions: There are no specific clinical manifestations for PBCs, thus, it is difficult in early diagnosis and treatment. According to Sanna's classification, preoperative FN and hearing function, the best surgical approach should be selected with minimal recurrences and perioperative morbidity.

Review: Male systemic lupus erythematosus: a review of sex disparities in this disease.

Although males with systemic lupus erythematosus (SLE) represent 4-22% of all SLE patients, it may not be appropriate that these cases should be subordinated to females with SLE in terms of most health-related issues. Over the past few decades, some distinctive features of male lupus have been observed with regard to genetic and environmental aspects of sex differences, clinical features, and outcome. In addition, recent insights into sex disparities in this disease have brought forth a few plausible and novel pathogenetic hypotheses. This review discusses these findings and sex disparities in SLE that appear to be especially noteworthy and pertinent to our understanding of male SLE.

[Surgical management of petrous bone cholesteatoma and facial nerve protection].

Objective: To discuss the therapeutic scheme of petrous bone cholesteatoma(PBC) and the technique of facial nerve reconstruction. Method: The data of 28 patients who underwent surgery for PBC in our center were analyzed retrospectively. All patients were diagnosed radiologically with PBCs and reconfirmed pathologically after surgery. The surgical approach was discussed basing Sanna's classification of PBCs, and the facial nerve outcomes were analyzed moreover. Result: PBC cases 11 were supralabyrinthine, 4 infralabyrinthine, 3 infralabyrinthine-apical, 10 massive and none apical. The facial nerve was involved in 50% of the cases. The translabyrinthine approach were used in 3 cases. The transotic approach was used in 7 cases in this series.The transcochlear approach type was applied in 12 cases. The Infratemporal fossa type B approach and subtotal petrosectomy were employed in 2 cases and 4 cases respectively. Active management of the nerve(rerouting, anastomosis, or grafting) was required in 14 cases, postoperative facial nerve function were inproved in 10 cases(71.43%). Conclusion: The appropriate surgery approach was vitally important to radical disease clearance in PBCs. The facial nerve preservation was preceded hearing preservation. Active facial nerve management were beneficial to facial nerve recovery..

MiR-630 promotes epithelial ovarian cancer proliferation and invasion via targeting KLF6.

OBJECTIVE: MicroRNAs play critical roles in post-translational gene expression. The current study was to investigate the effects of miR-630 in epithelial ovarian cancer. PATIENTS AND METHODS: Thirty epithelial ovarian cancer tissue and thirty normal ovarian tissue samples were collected and were detected miR-630 expression level with qRT-PCR. MiR-630 mimics, inhibitors and negative controls were transfected into SKOV3 and Cell Counting Kit-8 (CCK-8) assay, and transwell experiment were performed to detect the proliferation rate and migration, respectively. The luciferase reporter assay was utilized to identify miR-630's target gene. Balb/c nude mice were utilized to verify the effect of miR-630 in vivo. RESULTS: QRT-PCR showed a significantly high miR-630 expression in epithelial ovarian cancer relative to normal ovarian tissue. The miR-630 overexpression promoted epithelial ovarian cancer cell SKOV3 proliferation and migration. Krüppel-like factor 6 (KLF6) was predicted as the target of miR-630. In vivo study also verified that miR-630 overexpression stimulated ovarian cancer growth. CONCLUSIONS: We propose that targeting miR-630 might be a promising therapeutic approach for ovarian cancer.

Differential effect of gestation stage on benzo(a)pyrene-induced micronucleus formation and/or covalent DNA modifications in mice.

Benzo(a)pyrene (BP), an environmental carcinogen, binds ubiquitously to the DNA of maternal and fetal tissues (Lu et al., Cancer Res., 46: 3046-3054, 1986). These studies further investigated the effect of gestation age on the induction of genetic damage by BP. Timed-pregnant ICR mice were treated with one dose of BP on various days of gestation and sacrificed 24-120 h after treatment. At the molecular level, BP covalently bound to the DNA of adult bone marrow and fetal liver of mice at all gestation ages. Compared to the nonpregnant mice (adduct level = 15 adducts/10(8) bases), the adduct levels in the pregnant adult bone marrow were decreased up to 50% during early gestation (days 3-9) and then increased steadily to a 4-fold excess over nonpregnant values during late gestation (days 15-18). In the fetal liver, adduct levels exhibited little variation (3-4 adducts/10(8) bases) between days 11 and 15 of gestation and then increased sharply to 14 adducts/10(8) bases after day 16. At the cellular level, a higher percentage of polychromatic RBCs from adult and fetal mice after BP treatment contained micronuclei (MN) than controls (solvent or untreated). Bone marrow from pregnant mice exhibited greater increases in the formation of MN during early gestation (days 3-9) relative to late gestation (days 15-18), compared to the nonpregnant mice. In the fetuses, the amounts of MN formed were higher than those found in the adult nonpregnant or maternal mice, but these amounts decreased with gestation progression. Thus, MN induction with gestation progression differed from DNA adduction in adults and fetuses. In addition, the dose and time responses of MN formation also differed from those of covalent DNA modifications, when analyzed in the bone marrow of pregnant mice treated on gestation day 5. Collectively, our results showed that pregnancy and development modulate different types of genetic damage in different ways. Fetal tissues may be more sensitive than maternal tissues to genetic damage. Factors in addition to DNA adduct formation may be responsible for MN induction.

Mechanism of 5-azacytidine-induced transfer RNA cytosine-5-methyltransferase deficiency.

The administration of 5-azacytidine to mice leads to a specific, rapid, time-dependent, and dose-dependent decrease of transfer RNA (tRNA) cytosine-5-methyltransferase activity of mouse liver and the synthesis of tRNA specifically lacking 5-methylcytidine. The mechanism of this enzyme deficiency was investigated. The pretreatment of mice with RNA synthesis inhibitors such as actinomycin D and D-galactosamine prevented the enzyme deficiency induced by 5-azacytidine administration. These results suggested that RNA synthesis was a prerequisite for the induction by 5-azacytidine of the enzyme inhibition in vivo. Indeed, a slowly sedimenting RNA (4 to 7S) from the livers of mice treated with 5-azacytidine, when present in an in vitro tRNA methyltransferase assay, decreased specifically the activity of tRNA cytosine-5-methyltransferase. The pretreatment of mice with actinomycin D or D-galactosamine prior to the administration of 5-azacytidine effectively prevented the formation of such inhibitory RNA in vivo as determined by an in vitro tRNA methyltransferase assay. These results indicate that the administration of 5-azacytidine to mice leads to the rapid synthesis of a low-molecular-weight RNA fraction which is capable of specifically inactivating tRNA cytosine-5-methyltransferase activity in vivo and in vitro.

32P-postlabeling assay in mice of transplacental DNA damage induced by the environmental carcinogens safrole, 4-aminobiphenyl, and benzo(a)pyrene.

Transplacental exposure of fetuses to carcinogens is known to induce tumors in the offspring, often with a high incidence and short latency. While covalent adduction of DNA appears to be essential for tumor initiation, little is known about the binding of carcinogens to the DNA of fetal tissues. A sensitive 32P-postlabeling method enabled us to study the binding of the environmental carcinogens safrole (600 mumol/kg p.o.), 4-aminobiphenyl (800 mumol/kg), and benzo(a)pyrene (200 mumol/kg) to the DNA of various maternal and fetal tissues after administration of test carcinogens to pregnant ICR mice on day 18 of gestation. The results show that these carcinogens bound to the DNA of maternal and fetal liver, lung, kidney, heart, brain, intestine, skin, maternal uterus, and placenta, with organ-specific quantitative and qualitative differences. It was possible for the first time to analyze DNA adduct patterns in minute amounts of tissue, for example those available from fetal heart. The covalent binding index (mumol adducted nucleotides per mol of DNA nucleotides/mumol carcinogen administered per g body weight) 24 h after safrole treatment was estimated for the different organs and ranged from 0.1 to 247 and 0.1 to 5.8 for maternal and fetal DNA, respectively. Covalent binding index values of 0.2 to 13 and 0.1 to 0.3 for maternal and fetal DNA, respectively, were found for 4-aminobiphenyl. Benzo(a)pyrene treatment yielded covalent binding index values of 0.6 to 6.5 and 0.3 to 0.7 for maternal and fetal DNA, respectively. In both maternal and fetal tissues, safrole exhibited preferential binding to liver DNA. 4-Aminobiphenyl bound preferentially to DNA of maternal liver and kidney but showed no preference among fetal tissues. Benzo(a)pyrene exhibited weak tissue preference in both maternal and fetal organs. For all of the compounds studied, the fetal adduct levels were generally lower than the corresponding maternal adduct levels, especially when the level of maternal adduction was high. The major finding was that several carcinogens of diverse structure or their metabolites readily crossed the placenta and gave rise to DNA adducts in fetal organs. The resulting DNA damage in rapidly proliferating tissues may play a critical role in transplacental carcinogenesis.

Induction of covalent DNA modifications and micronucleated erythrocytes by 4-nitroquinoline 1-oxide in adult and fetal mice.

Pregnancy and development are known to modify carcinogenesis. Little is known about the mechanism for the modulation. These studies investigated the relative sensitivity of nonpregnant, pregnant, and fetal mice to the induction of covalent DNA modifications and micronucleated erythrocytes by 4-nitroquinoline 1-oxide (4-NQO). Our results revealed that 4-NQO was bound to guanine nucleotides of DNA in all maternal and fetal organs tested. The adduct levels ranged from 2-60 base modifications per 10(9) DNA bases when 4-NQO was administered s.c. Overall, 4-NQO bound preferentially to DNA of the maternal tissues compared with that of the corresponding fetal tissues, with the exception of the liver. The adduct levels in maternal and fetal organs fell into 3 distinct levels. The greatest binding was in maternal lungs and pancreas (the target organs for carcinogenesis). The lowest binding levels were in maternal liver and all fetal organs studied. Gestation age at the time of 4-NQO treatment did not produce a significant effect on the amounts of adduct formation in the tissues examined, with the exception of placenta and bone marrow. Chronic treatment did not affect binding preference. At the cellular level, 4-NQO treatment induced twice the frequency of micronucleated erythrocytes in the bone marrow of pregnant mice compared with the nonpregnant mice and fetal liver, on a mg/kg basis. However, the polychromatic erythrocytes of fetal liver were more sensitive than those of adult bone marrow to the induction of micronuclei, when adduct levels were taken into account. A positive correlation of organotropsim between 4-NQO-induced DNA adducts and carcinogenicity was observed for maternal tissues, but not for fetal tissues. Fetal tissues, overall, lack the enzymes to metabolically activate 4-NQO. Fetal cells elicit greater biological responses, compared with adult cells, at equal adduct levels. This study reveals that the effective doses in maternal and fetal tissues may differ and, therefore, will be a better basis for further understanding the molecular mechanism of transplacental carcinogenesis.

Age-, tissue-, and Ah genotype-dependent differences in the binding of 3-methylcholanthrene and its metabolite(s) to mouse DNA.

The induction of transplacental carcinogenesis by 3-methylcholanthrene (MC) in mice is determined, in part, by the genotype at the Ah locus. The relationship of Ah genotype and MC-induced DNA adducts was tested by comparing the response of pregnant and fetal C57BL/6 mice (Ahb Ahb; responsive to the induction of MC metabolism) and DBA/2mice (Ahd Ahd; nonresponsive). On day 17 of gestation (day 1 = presence of vaginal plug), C57BL/6 mice were treated i.p. with 100 mg/kg MC and DBA/2 mice with 30 mg/kg. Mice were sacrificed 24 h later and the tissues were analyzed for the presence of DNA adducts using the P1 nuclease version of the 32P-postlabeling method. With a 3.3-fold difference in administered dose, the total adduct levels in fetal DNA were (a) similar in both strains with the exception of liver, for which C57BL/6 mice had more adducts; (b) higher in the lung than skin, liver, or thymus; and (c) only 1/4 to 1/14 of the adult levels. Maternal DBA/2DNA contained more adducts in the thoracic lymph nodes and liver but fewer in the placenta and lung, compared to maternal C57BL/6 DNA. More adducts were detected in lung DNA than liver DNA in C57BL/6 mice. In contrast, these levels were similar in DBA/2 mice. When the difference in dose administered was considered in conjunction with this, less MC bound to DNA of C57BL/6 than DBA/2 mice overall. To identify adducts, oxidized metabolites of MC, 1-hydroxy-, 2-hydroxy-, 9,10-dihydrodiol-, or 3-methoxymethyl-MC, were topically applied to the dorsal skin of both strains. All of these metabolites produced adducts. Approximately 14 different adduct spots were detected. The two most abundant adducts were produced by 1-hydroxy-, 2-hydroxy-, and 9,10-dihydrodiol-MC. One of these also contained a 3-hydroxymethyl group. Several adducts did not contain the 9,10-dihydroxy group. The adducts derived from 3-methoxymethyl-MC were consistently found in greater abundance in DNA from C57BL/6 tissues, compared with DBA/2. Thus, oxidation of the 3-methyl group may be enhanced by Ah-dependent induction of MC metabolism. Together, these results suggest that the individual and total adduct levels are influenced by the genotype at the Ah locus, the route of administration, and the metabolite(s) with tissue and age specificity.