[Research progress in the diagnosis and management of proliferative verrucous leukoplakia].

Proliferative verrucous leukoplakia (PVL) is one of the oral potentially malignant disorders (OPMD) with the highest malignant potential. PVL tends to be easily misdiagnosed owing to the resemblance in clinical manifestations between PVL and other diseases such as oral leukoplakia or oral lichen planus. PVL is considered as a special type of oral leukoplakia by some scholars, which is characterized by its tendency of recurrence and metastasis, along with its high risk of malignant transformation. So far, the accurate clinic diagnosis and management of PVL are still intractable due to the lack of definite histopathological definition, unified diagnostic criteria and effective treatment modalities. This review aims to provide the clinical practitioners with a series of advices on the clinical diagnosis and management of PVL by systematically reviewing the diagnostic logistics, therapeutic strategies, malignant transformation detection based on tremendous relevant data and evidence-based medicine.

Structure-dependent electrical conductivity of protein: its differences between alpha-domain and beta-domain structures.

Electron transports in the α-domain and ß-domain of proteins have been comprehensively investigated. The structure-dependent electron transport of proteins has been experimentally measured and theoretically simulated, and both the theoretical and experimental results demonstrate significant differences in electrical conductivity between the α-domain and ß-domain. By controlling the feedback system of the scanning tunneling microscope (STM), the conductance of a single α-domain protein hemoglobin (Hgb) and a ß-domain protein superoxide dismutase enzyme (SOD) were measured, respectively. The current signal of Hgb is obviously stronger, indicating that the α-domain is more conductive. To confirm our finding, molecular orbitals of both the ß-domain in SOD and α-domain in Hgb have been analyzed based on first-principles calculations. As expected, tunneling transport and hopping in the α-domain are both more efficient, indicating that it is easier for electrons to transport through the α-domain, which are in great agreement with our experimental data. In order to explain our results, molecular structures of α- and ß-domains have been carefully analyzed and show that the explanation should lie in the differences in packing mode between the α-domain and ß-domain. This research should be very important to application prospects in molecular electronics.

Comparative pharmacokinetics and bioavailability of tylosin tartrate and tylosin phosphate after a single oral and i.v. administration in chickens.

The pharmacokinetics and oral bioavailability of tylosin tartrate and tylosin phosphate were carried out in broiler chickens according to a principle of single dose, random, parallel design. The two formulations of tylosin were given orally and intravenously at a dose level of 10 mg/kg b.w to chicken after an overnight fasting (n = 10 chickens/group). Serial blood samples were collected at different time points up to 24 h postdrug administration. A high performance liquid chromatography method was used for the determination of tylosin concentrations in chicken plasma. The tylosin plasma concentration's time plot of each chicken was analyzed by the 3P97 software. The pharmacokinetics of tylosin was best described by a one-compartmental open model 1st absorption after oral administration. After intravenous administration the pharmacokinetics of tylosin was best described by a two-compartmental open model, and there were no significant differences between tylosin tartrate and tylosin phosphate. After oral administration, there were significant differences in the Cmax (0.18 ± 0.01, 0.44 ± 0.09) and AUC (0.82 ± 0.05, 1.57 ± 0.25)between tylosin phosphate and tylosin tartrate. The calculated oral bioavailability (F) of tylosin tartrate and tylosin phosphate were 25.78% and 13.73%, respectively. Above all, we can reasonably conclude that, the absorption of tylosin tartrate is better than tylosin phosphate after oral administration.

Residue depletion of decoquinate in chicken tissues after oral administration.

A rapid, sensitive, and reliable high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed and validated for the analysis of decoquinate in chicken tissues. The compounds were extracted using acetonitrile by liquid-liquid extraction (LLE) and purified with an Oasis(™) HLB solid-phase extraction (SPE) cartridge. Chromatographic separation was performed on an XTerra C18 reversed-phase column with a mobile phase of water containing 0.1% formic acid and acetonitrile. The analyte was detected by tandem quadrupole mass spectrometry after positive electrospray ionization by multiple reaction monitoring. The detection and quantitation limits were 1 and 2.5 µg/kg, respectively. The recoveries of edible tissues ranged from 85.3% to 104.9%, with relative standard deviations (RSD) lower than 10.4%. The depletion profile of decoquinate was studied in healthy chickens after oral administration of feed containing 27.2 mg/kg decoquinate for 10 consecutive days. The residue concentrations of decoquinate in chicken muscle and liver were detected using the developed method. The highest residue concentrations were attained 0.25 day post-treatment, and decoquinate residues were still detected 5 days postmedication in the tissues examined. The developed method has been successfully applied to the depletion study of decoquinate in chicken tissues. The recommended withdrawal period with oral administration based on our research is 3 days.

Effect of three polyether ionophores on pharmacokinetics of florfenicol in male broilers.

Drug-drug interactions (DDIs) may adversely affect the prevention and cure of diseases. The effects of three polyether ionophore antibiotics, salinomycin (SAL), monensin (MON), and maduramycin (MAD) on the pharmacokinetics of florfenicol (FFC) were investigated in broilers. The chickens were fed rations with or without SAL (60 mg/kg feeds), MON (120 mg/kg feeds), or MAD (5 mg/kg feeds) for 14 consecutive days. FFC was given to the chickens either intravenously (i.v.) or orally (p.o.) at a single dose of 30 mg/kg body weight. Blood samples were taken from each chicken at 0-24 h postadministration of FFC. The plasma concentration of FFC was detected by high-performance liquid chromatography. The plasma concentration of FFC decreased with i.v. or p.o. co-administration of SAL, MON, or MAD in broilers, implying occurrence of DDIs during the co-administration of FFC with these ionophores. Our findings suggest that more attention should be given to the use of FFC to treat bacterial infections in chickens supplemented with polyether ionophore antibiotics.

First Report of Pine Wilt Disease Caused by Bursaphelenchus xylophilus on Pinus thunbergii in the Inland City of Zibo, Shandong, China.

The pinewood nematode (PWN) Bursaphelenchus xylophilus (Steiner & Buhrer 1934) Nickle 1970 is the causal agent of pine wilt disease. It is especially damaging in East Asian countries, including Japan, China, and Korea. In China, the nematode has been found in Anhui, Guangdoung, Guizhou, Chongqing, and Zhejiang Provinces since its discovery in Jiangsu Province in 1982 (1). China is confronted with an enormous threat to its pine forests. B. xylophilus is transmitted by the insect vector pine sawyer beetle (Monochamus alternatus). The main host trees are Pinus massoniana, P. thunbergii, and P. densiflora, which are the most common pine trees in China. Shandong Province, located north of Jiangsu Province, is a high-risk area because it was thought to be the northernmost suitable area for the pine wood nematode. P. tabulaeformis, P. densiflora, and P. thunbergii are the principal hosts. In 2010, a pine tree with suspected wilt disease was found in Lushang Forest (36°16'31.11″ N, 118°03'59.79″ E) of P. thunbergii located in Zibo city of Shandong Province. Symptoms were systemic, with almost all leaves brown or yellowish; the tree was nearly dead. Wood samples were collected and nematodes were extracted using a modified Baermann's funnel method. After 12 h, the nematodes were collected from the wood chips, and their morphology was observed with an inverted light microscope (Nikon 90i, Japan). Nematodes had a typical Aphelenchoid-type esophagus and female vulva flap. Females had subcylindrical tails, usually with broadly rounded terminus, some with a short mucro, and flat vulva, whereas males had large paired arcuate spicules with a sharply pointed prominent rostrum, and typical disc-like expansions on distal ends. Standard measurements of these nematodes were as follows: 25 females: body length = 960.9 ± 117.4 (791.5 to 1,265.2) µm, a = 32.1 ± 5.1 (23.7 to 44.5), b = 13.6 ± 1.4 (11.4 to 16.1), c = 28.3 ± 4.6 (21.7 to 42.2), V = 77.8 ± 2.0 (74.2 to 83.9), stylet length = 13.7 ± 1.6 (11.4 to 17.6) µm; 21 males: body length = 785.6 ± 103.2 (609.6 to 1,004.5) µm, a = 33.3 ± 4.4 (26.0 to 40.8), b = 11.9 ± 1.3 (9.0 to 14.6), c = 31.0 ± 2.7 (25.5 to 37.1), stylet length = 13.5 ± 1.9 (11.0 to 17.5) µm, spicule length = 18.8 ± 2.5 (14.9 to 23.9) µm. The morphometrics of this population, apart from body length and "a" value, which are shorter than the Portugal isolate measured by Mota et al. (3), are very much in the same range reported for B. xylophilus. For a more accurate identification, DNA was extracted from individual nematodes using a liquid nitrogen method. The internal transcribed spacers (ITS-1, ITS-2, 5.8S) were amplified by using PCR (2). Nucleotide sequences were compared with the sequences of B. xylophilus in GenBank, accession nos. JN684828 (Portugal), JN684829 (Portugal), JF826219 (Madeira Island) and JQ288086 (Japan). The ITS DNA sequences of the nematode from P. thunbergii were 99% identical to those of B. xylophilus in GenBank. A sequence of this nematode was submitted to the GenBank database and assigned the number KC460340. We have thus confirmed that B. xylophilus is now present north of Changjiang River in Zibo city, Shandong Province. This range expansion, perhaps the result of global warming, will affect both domestic and international quarantine efforts to control the further spread of pinewood nematode. References: (1) X. Y. Cheng et al. Heredity 100:356, 2008. (2) K. Metge and W. Burgermeister. J. Plant Dis. Protect. 113:275, 2006. (3) M. Mota et al. Nematology 1:727, 1999.

Gene expression and protein distribution of orexins and orexin receptors in rat retina.

Orexins, composed of orexin A and orexin B, are identified as endogenous ligands of two orphan G-protein-coupled receptors: orexin 1 and orexin 2 receptors (OX1R and OX2R). Orexins are implicated in regulating wake/sleep states, feeding behaviors, etc. Using reverse transcription-polymerase chain reactive (RT-PCR) analysis and immunofluorescence double labeling, we investigated the distributions of orexin A, orexin B, OX1R and OX2R in rat retina. RT-PCR analysis revealed the presence of mRNAs of prepro-orexin, OX1R and OX2R in rat retina. Immunostaining for orexin A and orexin B was observed in many cells in the inner nuclear layer and the ganglion cell layer. In the outer retina, horizontal cells, labeled by calbindin, and bipolar cells, labeled by homeobox protein Chx10, were orexin A- and orexin B-positive. In the inner retina, two orexins were both found in GABAergic amacrine cells (ACs), including dopaminergic and cholinergic ones, stained by tyrosine hydroxylase and choline acetyltransferase respectively. Glycinergic ACs, including AII ACs, also expressed orexins. Weak to moderate labeling for orexin A and orexin B was diffusely distributed in the inner plexiform layer. Additionally, orexins were expressed in almost all ganglion cells (GCs) retrogradely labeled by cholera toxin B subunit. Specifically, double-labeling experiments demonstrated that melanopsin-positive GCs (intrinsically photosensitive retinal GCs, ipRGCs) were labeled by two orexins. Morever, OX1R immunoreactivity was observed in most of GCs and all dopaminergic ACs, as well as in both outer and inner plexiform layers. In contrast, no obvious OX2R immunostaining was detectable in the rat retina. These results suggest that orexins may modulate the function of neurons, especially in the inner retina. We further hypothesize that the orexin signaling via ipRGCs may be involved in setting the suprachiasmatic nucleus (SCN) circadian clock.

Activation of the ζ receptor 1 suppresses NMDA responses in rat retinal ganglion cells.

The sigma receptor 1 (σR1) has been shown to modulate the activity of several voltage- and ligand-gated channels. Using patch-clamp techniques in rat retinal slice preparations, we demonstrated that activation of σR1 by SKF10047 (SKF) or PRE-084 suppressed N-methyl-D-aspartate (NMDA) receptor-mediated current responses from both ON and OFF type ganglion cells (GCs), dose-dependently, and the effect could be blocked by the σR1 antagonist BD1047 or the σR antagonist haloperidol. The suppression by SKF of NMDA currents was abolished with pre-incubation of the G protein inhibitor GDP-ß-S or the Gi/o activator mastoparan. We further explored the intracellular signaling pathway responsible for the SKF-induced suppression of NMDA responses. Application of either cAMP/the PKA inhibitor Rp-cAMP or cGMP/the PKG inhibitor KT5823 did not change the SKF-induced effect, suggesting the involvement of neither cAMP/PKA nor cGMP/PKG pathway. In contrast, suppression of NMDA responses by SKF was abolished by internal infusion of the phosphatidylinostiol-specific phospholipase C (PLC) inhibitor U73122, but not by the phosphatidylcholine-PLC inhibitor D609. SKF-induced suppression of NMDA responses was dependent on intracellular Ca2+ concentration ([Ca2+]i), as evidenced by the fact that the effect was abolished when [Ca2+]i was buffered with 10 mM BAPTA. The SKF effect was blocked by xestospongin-C/heparin, IP3 receptor antagonists, but unchanged by ryanodine/caffeine, ryanodine receptor modulators. Furthermore, application of protein kinase C inhibitors Bis IV and Gö6976 eliminated the SKF effect. These results suggest that the suppression of NMDA responses of rat retinal GCs caused by the activation of σR1 may be mediated by a distinct [Ca2+]i-dependent PLC-PKC pathway. This effect of SKF could help ameliorate malfunction of GCs caused by excessive stimulation of NMDA receptors under pathological conditions.

Effects of ionophores on liver CYP1A and 3A in male broilers.

The effects of ionophore antibiotics on the enzyme activity, protein and mRNA expression levels of cytochrome P450 (CYP) isoenzymes were investigated in liver from male Arbor Acres (AA) broiler chicks. Monensin, salinomycin and maduramycin at the dosage of 120, 60, and 5 mg/kg were administered in feed for 14 days. CYP1A and CYP3A activities were quantitated using cocktail probe drugs and a high performance liquid chromatographic (HPLC) assay at the 15th day; the protein expressions of CYP1A and CYP3A were detected by Western blot. CYP1A4, CYP1A5 and CYP3A37 mRNA levels were detected by real-time polymerase chain reaction (real-time PCR). Monensin, salinomycin and maduramycin had no effect on caffeine metabolism, protein expression and mRNA expression, but did induce dapsone metabolism, increasing CYP3A protein expression. However, there was no change in CYP3A37 mRNA expression as compared with the control group. It is suggested that ionophore antibiotics may have an induction effect on CYP3A expression and enzyme activity and that such effect might be related to the posttranscriptional regulation of its protein expression. Consideration of the enhanced metabolism of other drugs used simultaneously with ionophores is therefore recommended.

Antioxidant activities of extracts and flavonoid compounds from Oxytropis falcate Bunge.

The antioxidant properties of the various extracts and flavonoids prepared from Oxytropis falcate Bunge were investigated by 1,1-diphenyl-2-picryldydrazyl (DPPH) radical-scavenging assay. In the chloroform, ethyl acetate and n-butanol extracts, the ethyl acetate extract exhibited the highest antioxidant activity (IC(50) = 2.05 mg mL(-1)). Furthermore, rhamnocitrin, kaempferol, rhamnetin, 2',4'-dihydroxychalcone and 2',4', beta-trihydroxy-dihydrochalcone were purified from chloroform and ethyl acetate extracts. The radical-scavenging activities of the five compounds were also measured and the results showed that kaempferol (IC(50) = 0.11 mg mL(-1)), rhamnetin (IC(50) = 0.14 mg mL(-1)) and rhamnocitrin (IC(50) = 0.15 mg mL(-1)) exhibited considerable antioxidant activities, but the antioxidant activities of the two dihydrochalcones were very weak. Although these flavonoids are known, this is the first report of antioxidant activity in this plant.

Hyalinizing spindle cell tumor with giant rosettes: report of a case showing remarkable myofibroblastic differentiation.

We examined the proliferative activity and the differentiation line of tumor cells in a case of "hyalinizing spindle cell tumor with giant rosettes" (HSCGR). A 6 cm tumor within the right deltoid muscle of a 58-year-old female was found by physical and radiographical examinations. A biopsy revealed the histological features of a spindle cell tumor with rosette-like structures. Wide excision was done under the diagnosis of HSCGR. The tumor presented as a gray-whitish, solid mass with focal pseudocystic degeneration. Immunohistochemically, the tumor cells were diffusely positive for vimentin and were also focally positive for S-100, but negative for desmin and alpha-smooth muscle actin. The cells stained positively for Ki-67 with even distribution, there being a correlation with the cellularity of the areas, with a labeling index ranging from 0.3 to 0.5%. In addition, flow cytometry revealed an almost normal diploid DNA pattern and 5.8% S-phase fraction, indicating low proliferative activity. Ultrastructurally, many tumor cells displayed discontinuous basal lamina, pinocytotic vesicles, dilated rough endoplasmic reticulum, and microfilaments with focal dense bodies. The main component of the rosette was collagenous fibrils with normal diameter and normal periodic banding. We interpreted this case of HSCGR as a low grade fibrosarcoma with remarkable differentiation of myofibroblastic lineage, and with focally accumulated, morphologically normal collagenous fibrils.

Antitumor effect of bcl-2 antisense phosphorothioate oligodeoxynucleotides on human renal-cell carcinoma cells in vitro and in mice.

BACKGROUND AND PURPOSE: Programmed cell death is a genetically regulated pathway that is altered in many cancers. This process is, in part, regulated by the bcl-2 oncogene. Antisense oligodeoxynucleotides (ODNs) targeted to specific oncogenes have been used with some therapeutic success in animal models of leukemia and melanoma cells and human Hodgkin's lymphoma. We evaluated the effects of antisense ODNs targeted to the bcl-2 oncogene on the proliferation of human renal-cell carcinoma (RCC) cells in vitro and on the growth of human RCC xenografts in BALBc nude (nu/nu) mice. MATERIALS AND METHODS: Expression bcl-2 mRNA in five RCC cell lines (ACHN, Caki-1, RCZ, RCW, and OS-RC-2) was analyzed by reverse transcriptase-polymerase chain reaction. The effects of phosphorothioated ODNs containing human bcl-2 sense and bcl-2 antisense sequences that were transfected with Lipofectin on the proliferation and viability of cultures of established human RCC cell lines were determined by MTS assay. The expression of Bcl-2 protein in ACHN tumor cells following antisense bcl-2 (AS2) ODN treatment was evaluated by Western blot analysis, and the extent of apoptosis in these cells was determined by fluorescence-activated cell sorter (FACS) analysis. The antitumor activity in ACHN xenografts in nu/nu mice was monitored by measuring differences in tumor weight in treated and control mice. RESULTS: Expression of bcl-2 mRNA was detected in all five RCC lines. Treatment with antisense bcl-2 ODNs inhibited the growth of all tested RCC cells and decreased Bcl-2 protein expression in ACHN cells. The AS2 antisense ODN complementary to the coding region of bcl-2 mRNA showed a superior antiproliferative effect compared with AS1 ODN complementary to the translation initiation region. Inhibition by antisense bcl-2 ODNs of ACHN cells was dose dependent. The FACS analysis revealed that growth inhibition was associated with the induction of programmed cell death. In vivo, AS2 ODN antitumor activity was noted in locally injected groups. CONCLUSIONS: Treatment of human RCC with antisense ODNs targeted to bcl-2 inhibits growth and is associated with the induction of programmed cell death. These results suggest therapeutic use of antisense bcl2 in the treatment of RCC.

[Study on analysis of concentration of surfactant PS in injected-produced liquor used in ASP flooding with HPLC].

Ion exchanger and ODS bonded silica gel for HPLC packing were prepared. An HPLC method for the analysis of surfactant PS concentration in injected-produced liquor has been established to meet the need of ASP flooding developed in Gudao West Block of Shengli Oilfield, with a minimum detectable limit of 0.4 mg/L, a linear range of 50 mg/L-1,000 mg/L and recoveries of 95.7%-99.8%. This method has provided great technical support in a variety of fields to the design of the prescription for ASP flooding, the regulation of injection measurement, the quality control of products and the study on the mechanism of oil flooding etc.

Effect of experimental fasciolosis on antipyrine metabolism and clearance in water buffaloes.

The effect of chronic Fasciola hepatica infection on the metabolism of antipyrine, a marker of microsomal oxidative metabolism, was investigated in male water buffaloes dosed daily with 60 F. hepatica metacercariae over 20 days. The plasma elimination half-life of antipyrine was significantly elevated by 23% at 11 weeks postinfection (p.i.) but did not significantly differ from the control period at 20 weeks p.i. The systemic clearance of antipyrine decreased by 48% at 11 weeks p.i. and then returned to normal. The renal clearance for each of the main antipyrine metabolites decreased at 11 weeks p.i. (hydroxymethylantipyrine (HMA), -42%; norantipyrine (NORA), -58%; and 4-hydroxyantipyrine (OHA), -70%) and did not significantly differ from the control period at 20 weeks p.i. These findings indicate that experimental subclinical fasciolosis leads to altered antipyrine kinetics and to an inhibition of the different antipyrine metabolic pathways in water buffaloes.

Relationship between p53 gene mutation and protein expression: clinical significance in transitional cell carcinoma of the bladder.

Although the mutated p53 gene has been postulated to induce immunohistochemically-detectable p53 protein, reports regarding the relationship between p53 mutation and p53 protein expression have been contradictory. This study investigated the relationship between p53 mutations and p53 expression and their clinical significance for patients with transitional cell carcinoma of the bladder. Eighty-seven transitional cell carcinoma of the bladder were analyzed by immunohistochemistry (IHC) for p53 nuclear accumulation, and the results compared to mutations detected in the p53 gene evaluated by polymerase chain reaction single-strand conformation polymorphism (SSCP) and DNA sequence analysis. By p53 IHC analysis, positive p53 staining was observed in 50 (57.5%) of the 87 tumors. The specificity of IHC, defined as a percentage of IHC negative (<20%) tumors among tumors without mutation, was 94.6%. Despite the good concordance between p53 mutation and p53 protein expression (p<0.0001), 48.0% (24/50) of the tumors showed p53 overexpression without mutation, and 2 (5.4%) tumors with mutation showed no p53 immunoreactivity. Patients with higher grade (grade 3), stage (stages pT2-4), and p53 mutations had a poorer prognosis by Kaplan-Meier survival analysis. A Cox univariate analysis found that grading (hazard ratio 3.139; p=0.002), staging (hazard ratio 3.832; p=0.0005) and p53 mutation (hazard ratio 2.498; p=0.013) were significant variables in these patients, but no variable was independently associated with an increased survival of bladder carcinoma by multivariate analysis. We found that a 20% cut-off level of p53 overexpression showed the highest correlation with prognosis and p53 mutation, however, p53 overexpression and mutation were not superior to staging as prognostic markers. These data suggest that careful assessment of the TNM staging system remains the most reliable predictive indicator of survival for patients with transitional cell carcinoma of the bladder.

[Chiral separation of glycerin monosulfides and bisulfides with a stationary phase of amylose-tris(3,5-dimethylphenylcarbamate)].

Amylose-tris(3,5-dimethylphenylcarbamate) (ADMPC) and aminopropylated silica gel(APS) were prepared after the reported methods. ADMPC was immobilized on APS from tetrahydrofuran solution with a coating amount of 15%. The chiral stationary phase was packed in a stainless-steel column(150 mm x 4.6 mm i.d.) by slurry method. The column was used for the enantioseparation of 6 glycerin monosulfides and 4 glycerin bisulfides. Mixtures of hexane and 2-propanol were used as mobile phases. The enantiomers of the monosulfides could be separated quite well, while those of the bisulfides could not at all. This phenomenon shows that the ether oxygen atom of the monosulfides plays a key role in the chiral discrimination process. The retention time of the solutes increases significantly as the amount of 2-propanol decreases. This shows the main interaction between the solutes and the chiral stationary phase is hydrogen bonding. A dynamic model is presented to account for the chiral discrimination mechanism.

[Direct optical resolution of acidic biphenyl drugs by high performance liquid chromatography on tris(3,5-dimethylphenylcarbamate) of cellulose].

A chiral stationary phase was prepared by coating cellulose-tris(3, 5-dimethylphenylcarbamate) onto aminopropylated silica gel. A series of enantiomeric acidic biphenyl drugs were directly resolved on the chiral stationary phase (CSP) by normal-phase high performance liquid chromatography (HPLC). A hexane-2-propanol eluting system containing 1% of trifluoroacetic acid was used as mobile phase. Efficient optical resolution of the acidic biphenyl drugs has been attained. The factors that influence chiral discrimination such as structural characeristic of the samples and mobile phase were investigated. An interaction model between the stationary phase and the samples was discussed. The results showed that efficient optical resolution of racemic carboxylic acids could be attained by normal-phase HPLC on CSP using a hexane-2-propanol eluting system containing 1% of trifluoroacetic acid.

The significance of frequent and independent p53 and bcl-2 expression in large-cell neuroendocrine carcinomas of the lung.

Both p53 and bcl-2 genes are involved in regulating cell death. Reports, however, concerning the relationship between p53 and bcl-2 expression are contradictory. Large-cell neuroendocrine carcinoma (LCNEC) of the lung is a newly recognized clinicopathologic entity. p53 mutation and bcl-2 overexpression are frequent in small-cell lung carcinoma (SCLC), and we observed a close correlation between bcl-2 expression and cellular neuroendocrine (NE) differentiation in non-SCLC, so we speculated that LCNEC, an NE tumor closely related to SCLC, would exhibit high incidence of both p53 alteration and bcl-2 expression. Immunohistochemical expression of p53 and bcl-2 was evaluated on consecutive sections of 26 LCNECs, including 4 combined LCNECs. p53 accumulation and diffuse bcl-2 staining were observed in 18 (69.2%) of 26 and 24 (92.3%) of 26 LCNECs, respectively, but their immunoreactivities showed no fixed distribution relevance on consecutive sections in individual tumors. Statistical analyses yielded no relationship between p53 and bcl-2 expression (P = .47). In all of the four combined LCNECs, p53 was identically either positive or negative in both tumor cell populations with and without NE differentiation. bcl-2 immunoreactivity was observed only for the tumor cells with NE phenotype in three of the four combined LCNECs and was diffuse among the NE tumor cells but geographic in distribution among the non-NE tumor cells of the remaining one combined LCNEC. Thus, our present findings suggest that p53 and bcl-2 are expressed independently and might have distinct expression significance in LCNECs. A high incidence of p53 expression in LCNECs and equal p53 expression profiles in NE and non-NE tumor cell populations of combined LCNECs suggest that p53 alteration is primarily involved in the tumorigenesis of LCNEC. On the other hand, frequent bcl-2 expression in pure LCNECs and selective bcl-2 expression in tumor cells with NE phenotype in combined LCNECs are suggestive of a role for bcl-2 in regulating cellular NE differentiation.

Tumor extension and cell proliferation in adenocarcinomas of the lung.

To elucidate the mechanism of tumor extension in human pulmonary adenocarcinoma, we immunohistochemically investigated the expression of cell cycle regulator proteins in 54 small adenocarcinomas less than 3 cm in diameter. The Ki-67-labeling index was significantly higher in the periphery of the tumor nodule than in the center. This proliferative potential correlated well with coexpression of cdk2 and cyclin A. p27, one of the cdk inhibitors, was highly expressed in normal bronchial epithelial cells. Peripherally located tumor cells expressed p27 at an intermediate level, but at a higher frequency and level than those in the center. Expression of p21 was also predominant in the periphery. Furthermore, the expression patterns of p21 and p27 were reciprocal. In vitro kinase assays further demonstrated higher cdk2 kinase activity in the periphery. These results suggest that: (i) within an emerging extension made up of peripherally located tumor cells, their high proliferative potential gradually wanes as their relative topographical position becomes more central in the expanding tumor; (ii) peripherally located tumor cells maintain their proliferative potential by higher cyclin A-cdk2 complex activity; and (iii) intermediate expression of p21/p27 in the peripherally located cells promotes higher cyclin A-cdk2 kinase activity, whereas high p21/p27 expression in nonneoplastic cells inhibits kinase activity.