[Study of neuron-protective effect and mechanism of neuregulin1β against cerebral ischemia reperfusion-induced injury in rats]

Objective: Thecurrent study is to explore the neuron-protective mechanism of neuregulin1β (NRG1β) in a rat model of middle cerebral artery occlusion/reperfusion (MCAO/R) through inhibiting the c-Jun phosphorylation. Methods: After 24 h of MCAO/R (referring to Longa's method), neurobehavioral function was measured by modified neurological severity score (mNSS) test; the cerebral infarction volume was detected by triphenyltetrazolium chloride (TTC) staining; the blood brain barrier (BBB) permeability was measured by Evans Blue (EB); the neuron morphology of brain tissue was observed by Nissl stain; the ultra-structures of the neurons were observed by transmission electron microscopy (TEM); the apoptotic neurons were counted by in situ cell death detection kit colocalized with NeuN; the expressions of phospho-c-Jun was determined by immunofluorescent labeling and Western blot analysis. Results: Compared with the sham-operation rats, the rats receiving MCAO/R showed increased mNSS (9.7±1.2), cerebral infarction volume (41.4±3.0)%, permeability of BBB, deformation of neurons, ischemia-induced apoptosis (0.63±0.04), and enhanced expression of phospho-c-Jun protein (0.90±0.07) (all P<0.05). Our data indicated that NRG1β attenuated neurologic deficits (6.4±0.9), decreased the cerebral infarction volume (10.4±0.5), reduced EB extravasation (1.55±0.13) and the deformation of neurons, protected the ultra-structure of neurons, blocked ischemia-induced apoptosis (0.23±0.02), through down-regulated phospho-c-Jun expression (0.40±0.03) in MCAO/R rats (P<0.05). Conclusion: NRG1β exerts neuron-protective effects against ischemia reperfusion-induced injury in rats through inhibiting the c-Jun phosphorylation.

[Effects and related mechanism of quercetin on thrombin-induced proliferation and migration of rat vascular smooth muscle cells]

OBJECTIVE

To investigate the effects and related mechanism of quercetin on thrombin-induced proliferation and migration of rat vascular smooth muscle cells(VSMCs).

METHODS

Third to fifth generation VSMCs were divided into three groups, including control group (with PBS on the base of medium DMEM), thrombin group (with 1 U/ml thrombin on the base of medium DMEM) and quercetin group (treated with 100 μmol/L quercetin before 1 U/ml thrombin on the base of medium DMEM). The proliferation and migration capacitities were tested by CCK-8 kit and transwell chamber, respectively. The protein level of phospho-extracellular signal regulated kinase 1/2 and phosphor-p38 were measured by Western blot.

RESULTS

(1) According to the CCK-8 results, optical density value was significantly higher in thrombin group than that of control group(2.59±0.16 vs. 1.97±0.18, P<0.01), which could be significantly attenuated by pretreatment with quercetin(2.13±0.19, P<0.01), and there was no significant difference between quercetin group and control group(P>0.05). (2) The transwell results showed that the migrated VSMCs were significantly higher in thrombin group than in control group (1 337±162 vs. 99±26, P<0.01), which could be significantly reduced by pretreatment with quercetin (926±111, P<0.05), but still significantly higher than control group (P<0.01). (3) The protein expressions of phospho-extracellular signal regulated kinase 1/2 and phosphor-p38 were significantly upregulated in thrombin group compared to control group (both P<0.05), which could be significantly downregulated by pretreatment with quercetin (P<0.05).

CONCLUSION

Quercetin can effectively attenuate thrombin-induced vascular smooth muscle cells proliferation and migration, possibly through inhibiting the phosphorylation of extracellular signal regulated kinase 1/2 and p38 pathway.

Mutations that disrupt PHOXB interaction with the neuronal calcium sensor HPCAL1 impede cellular differentiation in neuroblastoma

Heterozygous germline mutations in PHOX2B, a transcriptional regulator of sympathetic neuronal differentiation, predispose to diseases of the sympathetic nervous system, including neuroblastoma and congenital central hypoventilation syndrome (CCHS). Although the PHOX2B variants in CCHS largely involve expansions of the second polyalanine repeat within the C-terminus of the protein, those associated with neuroblastic tumors are nearly always frameshift and truncation mutations. To test the hypothesis that the neuroblastoma-associated variants exert their effects through loss or gain of protein-protein interactions, we performed a large-scale yeast two-hybrid screen using both wild-type (WT) and six different mutant PHOX2B proteins against over 10 000 human genes. The neuronal calcium sensor protein HPCAL1 (VILIP-3) exhibited strong binding to WT PHOX2B and a CCHS-associated polyalanine expansion mutant but only weakly or not at all to neuroblastoma-associated frameshift and truncation variants. We demonstrate that both WT PHOX2B and the neuroblastoma-associated R100L missense and the CCHS-associated alanine expansion variants induce nuclear translocation of HPCAL1 in a Ca(2+)-independent manner, while the neuroblastoma-associated 676delG frameshift and K155X truncation mutants impair subcellular localization of HPCAL1, causing it to remain in the cytoplasm. HPCAL1 did not appreciably influence the ability of WT PHOX2B to transactivate the DBH promoter, nor did it alter the decreased transactivation potential of PHOX2B variants in 293T cells. Abrogation of the PHOX2B-HPCAL1 interaction by shRNA knockdown of HPCAL1 in neuroblastoma cells expressing PHOX2B led to impaired neurite outgrowth with transcriptional profiles indicative of inhibited sympathetic neuronal differentiation. Our results suggest that certain PHOX2B variants associated with neuroblastoma pathogenesis, because of their inability to bind to key interacting proteins such as HPCAL1, may predispose to this malignancy by impeding the differentiation of immature sympathetic neurons.

Clinical and molecular characterization of a Han Chinese family with high penetrance of essential hypertension

Mutations in mitochondrial DNA are associated with cardiovascular diseases. We reported here molecular characterization of a three-generation Han Chinese family with maternally transmitted hypertension. Most strikingly, this family exhibited a high penetrance of hypertension. Sequence analysis of mitochondrial genome showed the presence of 12,338T>C mutation and 12,330A>G mutation and distinct sets of polymorphisms belonging to the Asian haplogroup F2b. Interestingly, the well-known 12,338T>C mutation, which caused a change of methionine in the translational initiation codon of ND5, also localized in two nucleotides adjacent to the 3' end of tRNA(Leu(CUN)), was implied to cause a decrease in ND5 mRNA level as well as to alter tRNA(Leu(CUN)) stability level. Moreover, the highly conserved 12,330A>G mutation, which disrupted the base pairing (6T-67A) in acceptor arm of tRNA(Leu(CUN)), may result in the failure of tRNA(Leu(CUN)) metabolism. Therefore, the combination of ND5 12,338T>C and tRNA(Leu(CUN)) 12,330A>G mutations may contribute to the high penetrance of hypertension in this Chinese family.

Low prevalence of human papillomavirus (HPV) in Chinese patients with breast cancer

This retrospective study investigated the presence of human papillomavirus (HPV) in Chinese women with breast cancer, and the correlation between HPV infection and carcinogenesis. Tumour and non-cancerous breast tissue samples were obtained from 62 female patients with breast cancer; normal breast tissue samples were obtained from 46 women without breast cancer. HPV DNA was detected by nested polymerase chain reaction using consensus primers; HPV subtypes were determined by reverse dot blot and pyrosequencing analyses. HPV was found in tumour tissue samples from four of the 62 patients (6.5%), while no HPV DNA was detected in either the non-cancerous samples from patients with breast cancer or from the normal breast tissue controls. Of the four HPV-positive cases, three were HPV 16 positive (75%) and one was HPV 18 positive (25%). The low frequency of HPV detected in this study suggests that this infection is not a major risk factor in breast cancer development.

FP3: a novel VEGF blocker with antiangiogenic effects in vitro and antitumour effects in vivo

BACKGROUND Vascular endothelial growth factor (VEGF) is a critical promoter of blood vessel growth during embryonic development and neovascularisation in tumours. VEGF serves as a logical target for antiangiogenic cancer therapy because of its fundamental role in tumour angiogenesis. This study is to investigate the inhibitory effects of FP3, a novel VEGF blocker, on angiogenesis in vitro and tumour growth in vivo. METHODS The inhibitory effects of FP3 on angiogenesis in vitro were evaluated by using human umbilical vein endothelial cells (HUVECs) and rat aortic ring. The inhibitory effects of FP3 on tumour growth and angiogenesis in vivo were evaluated in a human non-small-cell lung cancer (NSCLC) cell line A549 tumour xenograft model with the methods of tumour growth regression assay and immunohistochemical staining, respectively. RESULTS In experiments with HUVECs, FP3 inhibited cell proliferation and migration. In rat aortic ring assay, FP3 suppressed VEGF-induced vessel sprouting. In tumour growth regression assay, FP3 significantly blocked the growth of A549 tumour in the subcutaneous tumour xenograft model and dramatically decreased the vessel density of tumour. CONCLUSIONS FP3 has excellent inhibitory effects on tumour angiogenesis both in vitro and in vivo, therefore it could be used as an effective antiangiogenic agent.

Study on the relationship between TSHR gene and thyroid diseases

Thyroid stimulating hormone receptor (TSHR) is thought to play a critical role in the pathogenesis of certain thyroid diseases, including Graves' disease (GD), multinodular thyroid goiter (MTG), and Hashimoto's thyroiditis (HT). In order to understand whether single nucleotide polymorphisms in the TSHR gene contribute to thyroid diseases, we have conducted a case-control study in which, we examined 8 TSHR gene single-nucleotide polymorphisms in introns 1, 4, 5, 6 and exons 7 and 8, respectively, among patients with thyroid diseases. These included one family with GD (3 patients and 9 healthy members); 60 patients with familiar thyroid diseases (30 with GD, 20 with MTG, and 10 with HT patients), 48 sporadic patients with GD and 96 healthy control individuals. Direct sequencing of all 10 exons and part of introns of TSHR gene, in these patients as well as healthy controls revealed eight polymorphisms. A novel polymorphism in exon 8 AGA(Arg) → CGA(Arg). However, there were no significant differences between patients and controls in the incidence of these polymorphisms. These results suggest that the polymorphisms (polymorphism in intron 1 at 81 bp upstream of exon 2; polymorphism in intron 4 at 135 bp upstream of exon 5; polymorphism in intron 4 at 365 bp upstream of exon 5; polymorphism in intron 5 at 69 bp upstream of exon 6; means polymorphism in intron 6 at 13 bp downstream of exon 6; polymorphism in intron 6 at 187 bp upstream of exon 7; E7+16: polymorphism in 16 bp of exon 7; polymorphism in 40 bp of exon 8) of the TSHR gene may not contribute to the pathogenesis of thyroid diseases.

Prevalence of human papillomavirus in Chinese patients with colorectal cancer

AIM

The prevalence of human papillomavirus (HPV) was determined in Chinese patients with colorectal cancer (CRC). The study also aimed to determine whether the HPV DNA peripheral blood (PB) assay can be used to diagnose HPV-related CRC.

METHOD

Tumour tissue, noncancerous colorectal tissue and whole-blood samples were obtained from 96 patients with CRC. In addition, 32 colorectal tissue samples were harvested from patients without CRC, and 48 whole-blood samples were collected from healthy blood donors. HPV DNA was detected by means of a nested polymerase chain reaction (PCR) using consensus primers, and HPV genotypes were determined by reverse Southern blot and pyrosequencing.

RESULTS

HPV DNA was detected in 32 of the 96 patients with CRC, and colorectal tissues from the 32 control patients without CRC were negative for HPV DNA (P < 0.001). Among 48 healthy donors, three had detectable levels of HPV DNA in their PB. Patients with CRC did not have significantly higher levels of HPV DNA than controls. The HPV prevalence in tumour tissues was higher than that in noncancerous colorectal tissues (P < 0.001) or that in PB samples (P < 0.001). No correlation between the presence of HPV and demographic or medical characteristics was observed. HPV 16 was the viral type most frequently detected and was found in 33 (94%) of 35 HPV-positive patients.

CONCLUSION

HPV infection may be a risk factor for CRC. However, detection of HPV DNA in PB does not appear to reflect the HPV status of CRC.

Silencing of ferrochelatase enhances 5-aminolevulinic acid-based fluorescence and photodynamic therapy efficacy

Background:

Recurrence of glioma frequently occurs within the marginal area of the surgical cavity due to invading residual cells. 5-Aminolevulinic acid (5-ALA) fluorescence-guided resection has been used as effective therapeutic modalities to improve discrimination of brain tumour margins and patient prognosis. However, the marginal areas of glioma usually show vague fluorescence, which makes tumour identification difficult, and the applicability of 5-ALA-based photodynamic therapy (PDT) is hampered by insufficient therapeutic efficacy in glioma tissues.

Methods:

To overcome these issues, we assessed the expression of ferrochelatase (FECH) gene, which encodes a key enzyme that catalyses the conversion of protoporphyrin IX (PpIX) to heme, in glioma surgical specimens and manipulated FECH in human glioma cell lines.

Results:

Prominent downregulation of FECH mRNA expression was found in glioblastoma tissues compared with normal brain tissues, suggesting that FECH is responsible for PpIX accumulation in glioblastoma cells. Depletion of FECH by small interference RNA enhanced PpIX fluorescence after exposure to 5-ALA concomitant with increased intracellular PpIX accumulation in glioma cells. Silencing of FECH caused marked growth inhibition and apoptosis induction by PDT in glioma cells.

Conclusion:

These results suggest that knockdown of FECH is a potential approach to enhance PpIX fluorescent quality for optimising the subjective discrimination of vague fluorescence and improving the effect of 5-ALA-PDT.

Identification of claudin-4 as a marker highly overexpressed in both primary and metastatic prostate cancer

In the quest for markers of expression and progression for prostate cancer (PCa), the majority of studies have focussed on molecular data exclusively from primary tumours. Although expression in metastases is inferred, a lack of correlation with secondary tumours potentially limits their applicability diagnostically and therapeutically. Molecular targets were identified by examining expression profiles of prostate cell lines using cDNA microarrays. Those genes identified were verified on PCa cell lines and tumour samples from both primary and secondary tumours using real-time RT–PCR, western blotting and immunohistochemistry. Claudin-4, coding for an integral membrane cell-junction protein, was the most significantly (P<0.00001) upregulated marker in both primary and metastatic tumour specimens compared with benign prostatic hyperplasia at both RNA and protein levels. In primary tumours, claudin-4 was more highly expressed in lower grade (Gleason 6) lesions than in higher grade (Gleason ⩾7) cancers. Expression was prominent throughout metastases from a variety of secondary sites in fresh-frozen and formalin-fixed specimens from both androgen-intact and androgen-suppressed patients. As a result of its prominent expression in both primary and secondary PCas, together with its established role as a receptor for Clostridium perfringens enterotoxin, claudin-4 may be useful as a potential marker and therapeutic target for PCa metastases.

Healthcare worker's perceptions of barriers to care by immigrant women with postpartum depression: an exploratory qualitative study

OBJECTIVE

We interviewed healthcare workers working in Toronto, Canada, regarding their experience of providing care to recent immigrant women suffering from postpartum depression. The objective was two-fold: 1) to identify potential barriers to care that recent immigrant women may encounter as perceived by healthcare workers; and 2) to identify challenges healthcare workers felt that they faced as providers of care to this population.

METHODS

Qualitative semi-structured interviews were conducted with 16 key informants from various disciplines employed by healthcare agencies providing care to postpartum immigrant women in Toronto. Constant comparative analysis was used to analyze the data.

RESULTS

Two main categories of barriers to care for recent immigrant women were identified: 'practical barriers' and 'culturally determined barriers'. Practical barriers included knowing where and how to access services, and language difficulties. Cultural barriers included fear of stigma and lack of validation of depressive symptoms by family and society. The challenges experienced by healthcare providers working with this population were organized into two other categories: 'professional limitations', and 'social/cultural barriers'. 'Professional limitations' included fear of incompetence, language barriers, and inadequate assessment tools. 'Social/cultural barriers' included the experience of cultural uncertainty.

CONCLUSIONS

The results suggest that not only are there important barriers to accessing postpartum care for recent immigrant women, but it can also be challenging for healthcare workers to deliver such needed care. Understanding some of these barriers and challenges from the perspective of healthcare providers is an important step to remedying gaps and obstacles in the service system.

The clinical value of hepatocyte growth factor and its receptor--c-met for liver cancer patients with hepatectomy

BACKGROUND

To study the dynamic change of hepatocyte growth factor after hepatectomy in patients with primary liver cancer, and to analyse the prognostic value of hepatocyte growth factor and c-met for these patients.

METHODS

Thirty-one consecutive patients undergoing partial hepatectomy for liver cancer were studied. Serum hepatocyte growth factor level was determined by using enzyme-linked immunosorbent assay kit before and after operation, respectively. C-met protein and MRNA expressions in cancerous and paracancerous tissues were examined by immunohistochemical and RT-PCR methods, respectively. The correlations between clinical-pathologic parameters and the expressions of hepatocyte growth factor in serum and c-met in cancerous tissues were analysed, respectively.

RESULTS

Liver cancer patients had a significantly higher level of serum hepatocyte growth factor than normal controls (1.0424+/-0.498 ng/ml versus 0.685+/-0.115 ng/ml, p=0.008). Serum hepatocyte growth factor level was positively affected by tumour size, node cirrhosis, portal vein tumour thrombi, cholangiocarcinoma (including combined hepatocellular carcinoma), poorly differentiated hepatocellular carcinoma and tumour recurrence or metastases. After hepatectomy, serum hepatocyte growth factor level peaked on the third postoperative day, and then declined, but did not return to normal level on the postoperative day 10. From the preoperative day to postoperative day 10, the level of serum hepatocyte growth factor had a decrease of percent (85.33+/-10.2%) in the group with large tumours (>5 cm), but an elevation of percent (121.9+/-10.3%) in the group with small tumours (<or=5 cm). From the preoperative day to postoperative day 3, the level of serum hepatocyte growth factor had a higher elevation in the group with major resection than in the group with local resection (p=0.016). Moderately or strongly positive expression of c-met protein was observed in 27 cancerous regions (27/31), and only in 5 paracancerous regions. The intensive expression of c-met MRNA was 100% (31/31) detectable in the cancerous tissues, but only 22.6% (7/31) in the paracancerous tissues. C-met protein expression in cancerous tissues was correlated with portal vein tumour thrombi, cholangiocarcinoma and tumour recurrence or metastases, and the expression in paracancerous tissues was correlated with node cirrhosis. No significant correlation was observed between the hepatocyte growth factor in serum and c-met in cancerous tissues.

CONCLUSION

The over-expressions of the hepatocyte growth factor and c-met indicates an adverse prognosis for patients with liver cancer. The sustained high level of serum hepatocyte growth factor after hepatectomy may be a factor related to early tumour recurrence and metastasis. Liver regeneration may be a main factor leading to high level of serum hepatocyte growth factor in early postoperative stage.

Employment of liver tissue slice analysis to assay hepatotoxicity linked to replicative and nonreplicative adenoviral agents

Whereas virotherapy has emerged as a novel and promising approach for neoplastic diseases, appropriate model systems have hampered preclinical evaluation of candidate conditionally replicative adenovirus agents (CRAds) with respect to liver toxicity. This is due to the inability of human viral agents to cross species. We have recently shown the human liver tissue slice model to be a facile means to validate adenoviral replication. On this basis, we sought to determine whether our ex vivo liver tissue slice model could be used to assess CRAd-mediated liver toxicity. We analyzed and compared the toxicity of a conditionally replicative adenovirus (AdDelta24) to that of a replication incompetent adenovirus (Adnull [E1-]) in mouse and human liver tissue slices. To accomplish this, we examined the hepatic apoptosis expression profile by DNA microarray analyses, and compared these results to extracellular release of aminotransferase enzymes, along with direct evidence of apoptosis by caspase-3 immunhistochemical staining and TUNEL assays. Human and mouse liver tissue slices demonstrated a marked increase in extracellular release of aminotransferase enzymes on infection with AdDelta24 compared to Adnull. AdDelta24-mediated liver toxicity was further demonstrated by apoptosis induction, as detected by caspase-3 immunohistochemical staining, TUNEL assay and microarray analysis. In conclusion, concordance of CRAd-mediated apoptosis in both the human and the mouse liver tissue slice models was demonstrated, despite the limited replication ability of CRAds in mouse liver slices. The results of this study, defining the CRAd-mediated apoptosis gene expression profiles in human and mouse liver, may lay a foundation for preclinical liver toxicity analysis of CRAd agents.

[The medium conditioned incubation with rat heart cells maintains the properties of ES cells]

17 kinds of conditioned media were selected by plating tests, propagation and other tests with two cell lines, C-19-2 and MESPU-13. The results suggested that the rat heart cells conditioned media (RH-CM) can inhibit the spontaneous differentiation effectively, maintain the normal diploid karyotypes and promote adherence and proliferation of mouse ES cells. The ES cells were propagated in RH-CM to the 20th passage remaining their pluripotent in vivo and in vitro differentiation ability. RH-CM can be used as supplement of ES cell media. ES cells which are cultured in media containing 70% RH-CM and on PMEF feeder can maintain their undifferentiation state and diploid karyotype. RT-PCR detection suggested that there was mLIF expression in rat heart cells.

Overexpression of GDNF induces and maintains hyperinnervation of muscle fibers and multiple end-plate formation

This study examined the role of glial cell line-derived neurotrophic factor (GDNF) in synaptic plasticity at the developing neuromuscular junction. Transgenic mice overexpressing GDNF in skeletal muscle under the myosin light chain-1 promoter were isolated. Northern blot and ELISA at 6 weeks of age indicated that GDNF mRNA and protein levels were elevated threefold in the lateral gastrocnemius muscle (LGM) of the GDNF-transgenic animals. Histochemical examination of LGM tissue sections at 6 weeks of age revealed a 70% increase in the number of cholinesterase-positive end plates without changes in end-plate area. Multiple end plates on a single muscle fiber were also observed, in addition to multiple axonal processes terminating on individual end plates. No change in the number of spinal motoneurons, overall LGM size, or muscle type composition was observed. Finally, overexpression of GDNF in muscle caused hypertrophy of neuronal somata in dorsal root ganglia without affecting their number. These findings demonstrate that overexpression of a single neurotrophic factor in skeletal muscle induces multiple end-plate formation and maintains hyperinnervation well beyond the normal developmental period. We suggest that GDNF, a muscle-derived motoneuron neurotrophic factor, serves an important role in the regulation of synaptic plasticity in the developing and adult neuromuscular junction.

Lobeline inhibits the neurochemical and behavioral effects of amphetamine

Lobeline interacts with the dopamine transporter and vesicular monoamine transporter, presynaptic proteins involved in dopamine storage and release. This study used rodent models to assess lobeline-induced inhibition of the neurochemical and behavioral effects of amphetamine. Rat striatal slices were preloaded with [(3)H]dopamine and superfused with lobeline for 30 min, and then with d-amphetamine (0.03-3.00 microM) plus lobeline for 60 min. As predicted, lobeline (1-3 microM) intrinsically increased (3)H overflow but did not inhibit d-amphetamine-evoked (3)H overflow. Consequently, the effect of lobeline on d-amphetamine-evoked endogenous dopamine and dihydroxyphenylacetic acid overflow was assessed. Lobeline (0.1-1 microM) inhibited d-amphetamine (1 microM)-evoked dopamine overflow but did not inhibit electrically evoked (3)H overflow, indicating a selective inhibition of this effect of d-amphetamine. To determine whether the in vitro results translated into in vivo inhibition, the effect of lobeline (0.3-10.0 mg/kg) pretreatment on d-amphetamine (0.1-1.0 mg/kg)-induced hyperactivity in rats and on d-methamphetamine (0.1-3.0 mg/kg)-induced hyperactivity in mice was determined. Doses of lobeline that produced no effect alone attenuated the stimulant-induced hyperactivity. Lobeline also attenuated the discriminative stimulus properties of d-methamphetamine in rats. Acute, intermittent, or continuous in vivo administration of lobeline (1-30 mg/kg) did not deplete striatal dopamine content. Thus, lobeline inhibits amphetamine-induced neurochemical and behavioral effects, and is not toxic to dopamine neurons. These results support the hypothesis that lobeline redistributes dopamine pools within the presynaptic terminal, reducing pools available for amphetamine-induced release. Collectively, the results support a role for lobeline as a potential pharmacotherapy for psychostimulant abuse.

Acute and chronic effects of nornicotine on locomotor activity in rats: altered response to nicotine

RATIONALE

Nicotine, a tobacco alkaloid, is known to be important in the acquisition and maintenance of tobacco smoking. Nornicotine, an active nicotine metabolite, stimulates nicotinic receptors and may produce psychomotor effects similar to nicotine.

OBJECTIVE

The present study determined the effects of acute and repeated administration of nornicotine on locomotor activity and compared its effects with those of nicotine.

METHODS

R(+)-Nornicotine (0.3-10 mg/kg), S(-)-nornicotine (0.3-10 mg/kg), S(-)-nicotine (0.1-1 mg/kg) or saline was administered s.c. to rats acutely or repeatedly (eight injections at 48-h intervals). Activity was recorded for 50 min immediately after each injection.

RESULTS

S(-)-Nicotine produced transient hypoactivity, followed by dose-related hyperactivity. Repeated S(-)-nicotine administration resulted in tolerance to the hypoactivity and sensitization to the hyperactivity. Subsequent testing following a saline injection revealed evidence of conditioned hyperactivity. Acute administration of 0.3 mg/kg or 1 mg/kg R(+)- or S(-)-nornicotine produced no effect. Transient hypoactivity was observed at 3 mg/kg and 10 mg/kg R(+)-nornicotine and at 10 mg/kg S(-)-nornicotine. However, rebound hyperactivity was not observed following acute administration of either nornicotine enantiomer, suggesting that nornicotine-induced psychomotor effects differ qualitatively from those of S(-)-nicotine. Repeated R(+)-nornicotine resulted in tolerance to the transient hypoactivity, however hyperactivity was not observed. Repeated S(-)-nornicotine resulted in tolerance to the hypoactivity and the appearance of hyperactivity. Repeated administration of either nornicotine enantiomer resulted in a dose-dependent alteration in response to a 1 mg/kg S(-)-nicotine challenge, suggesting some commonalities in the mechanism of action.

CONCLUSION

Nornicotine likely contributes to the neuropharmacological effects of nicotine and tobacco use.

[The relationship between apolipoprotein E gene polymorphism and coronary heart disease and arteriosclerotic cerebral infarction]

OBJECTIVE

To detect the relationship between ApoE gene polymorphism and coronary heart disease(CHD), arteriosclerotic cerebral infarction(ACI).

METHODS

Exon 4 of ApoE gene was analyzed in normal group(87 cases), CHD group(78 cases) and ACI group(55 cases) by a combination of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and direct AgNO(3) staining technique.

RESULTS

Between the control group and CHD group, ACI group, chi(2) test showed no significant difference in genotype of E3/E3 (P>0.5, P>0.1, respectively); while mu test showed no significant difference in allele epsilon(2)(P>0.25, P>0.1, respectively), epsilon(4)(P>0.1, P>0.25, respectively) of ApoE.

CONCLUSION

No relationship between ApoE gene polymorphism and CHD and ACI was noted in this study.

A Markov chain model to assess the efficacy of screening for non-insulin dependent diabetes mellitus (NIDDM)

BACKGROUND

The high prevalence and severe consequences of non-insulin dependent diabetes mellitus (NIDDM) in Taiwan calls for urgent measures to detect this disease in the asymptomatic phase. However, the efficacy of early detection of NIDDM is highly dependent on its natural history from the disease-free state, through the asymptomatic to the symptomatic phase and death from NIDDM or other causes.

METHODS

In order to project the above progression, a five-state illness-and-death Markov chain model was proposed to estimate these transition parameters using data from two rounds of a blood sugar screening programme for NIDDM in Puli, in central Taiwan.

RESULTS

Results showed that the annual incidence for asymptomatic NIDDM was 10.67 per 1000 (95% CI: 8.26-13.79) and the average duration between the asymptomatic and symptomatic phases (the sojourn time) was 8 years (95%CI: 5.74-11.29). The 10-year survival rate for asymptomatic NIDDM (79.35%) was better than that for symptomatic NIDDM (69.45%). Prediction of deaths from NIDDM was performed to assess how the efficacy of screening for NIDDM varied by different screening frequencies (annual, biennial, 4-yearly and the control group). Results indicated there is no substantial difference in mortality reduction from NIDDM among the annual, biennial and 4-yearly screening regimens. However, a 4-yearly screening regimen significantly reduced deaths from NIDDM by 40% (95% CI: 26-51%).

CONCLUSIONS

A long sojourn time and the substantial reduction in mortality suggest that a 4-yearly screening regime for NIDDM would be most effective and feasible in Taiwan. The proposed five-state Markov chain model can be applied to other similar NIDDM screening projects.

(S)-(-)-Cotinine, the major brain metabolite of nicotine, stimulates nicotinic receptors to evoke [3H]dopamine release from rat striatal slices in a calcium-dependent manner

Cotinine, a major peripheral metabolite of nicotine, has recently been shown to be the most abundant metabolite in rat brain after peripheral nicotine administration. However, little attention has been focused on the contribution of cotinine to the pharmacological effects of nicotine exposure in either animals or humans. The present study determined the concentration-response relationship for (S)-(-)-cotinine-evoked 3H overflow from superfused rat striatal slices preloaded with [3H]dopamine ([3H]DA) and whether this response was mediated by nicotinic receptor stimulation. (S)-(-)-Cotinine (1 microM to 3 mM) evoked 3H overflow from [3H]DA-preloaded rat striatal slices in a concentration-dependent manner with an EC50 value of 30 microM, indicating a lower potency than either (S)-(-)-nicotine or the active nicotine metabolite, (S)-(-)-nornicotine. As reported for (S)-(-)-nicotine and (S)-(-)-nornicotine, desensitization to the effect of (S)-(-)-cotinine was observed. The classic nicotinic receptor antagonists mecamylamine and dihydro-beta-erythroidine inhibited the response to (S)-(-)-cotinine (1-100 microM). Additionally, 3H overflow evoked by (S)-(-)-cotinine (10-1000 microM) was inhibited by superfusion with a low calcium buffer. Interestingly, over the same concentration range, (S)-(-)-cotinine did not inhibit [3H]DA uptake into striatal synaptosomes. These results demonstrate that (S)-(-)-cotinine, a constituent of tobacco products and the major metabolite of nicotine, stimulates nicotinic receptors to evoke the release of DA in a calcium-dependent manner from superfused rat striatal slices. Thus, (S)-(-)-cotinine likely contributes to the neuropharmacological effects of nicotine and tobacco use.

Cyclooxygenase-2 expression is up-regulated in human pancreatic cancer

A large body of evidence suggests that cyclooxygenase-2 (COX-2) is important in gastrointestinal cancer. The purpose of this study was to determine whether COX-2 was expressed in adenocarcinoma of the human pancreas. Quantitative reverse transcription-PCR, immunoblotting, and immunohistochemistry were used to assess the expression of COX-2 in pancreatic tissue. Levels of COX-2 mRNA were increased by >60-fold in pancreatic cancer compared to adjacent nontumorous tissue. COX-2 protein was present in 9 of 10 cases of adenocarcinoma of the pancreas but was undetectable in nontumorous pancreatic tissue. Immunohistochemical analysis showed that COX-2 was expressed in malignant epithelial cells. In cultured human pancreatic cancer cells, levels of COX-2 mRNA and protein were induced by treatment with tumor-promoting phorbol esters. Taken together, these results suggest that COX-2 may be a target for the prevention or treatment of pancreatic cancer.

Telomerase activity in the differentiation of benign and malignant adrenal tumors

BACKGROUND

Telomerase is an RNA-dependent DNA polymerase that extends the ends of chromosomes by synthesizing the 6 oligonucleotide repeat TTAGGG and thus serves as a marker for cellular immortality. Although absent in most adult somatic tissues, telomerase activity is present in stem cells and is reactivated in nearly all primary human malignancies. In this study we sought to determine whether tumors of the adrenal glands contain telomerase activity and whether telomerase activity can be used to differentiate benign and malignant tumors of the adrenal glands.

METHODS

Tissue was obtained from 23 specimens at adrenalectomy. Adjacent normal adrenal tissue was obtained for control. All specimens were rapidly frozen and stored at -80 degrees C until assay. Telomerase activity was determined by the telomeric repeat amplification protocol (TRAP).

RESULTS

Telomerase activity was present in 5 of 23 (22%) of the adrenal tumors. All 3 malignant tumors were strongly TRAP positive. There was a single cortical adenoma that had very weak telomerase activity. The single TRAP-positive tumor of the adrenal medulla was a ganglioneuroma.

CONCLUSIONS

Benign adrenal tumors infrequently contain telomerase activity, whereas telomerase reactivation appears to be common in malignant tumors of the adrenal glands. These data suggest that determination of telomerase activity may offer a novel way to facilitate the differentiation of benign and malignant adrenal tumors.

Antiviral activities of methylated nordihydroguaiaretic acids. 2. Targeting herpes simplex virus replication by the mutation insensitive transcription inhibitor tetra-O-methyl-NDGA

We had previously reported that tetramethyl-O-NGDA (M4N), a synthetic derivative of the naturally occurring nordihydroguaiaretic acid (NDGA), is able to inhibit HIV Tat transactivation by blocking host Sp1 protein at the Sp1 cognate binding site on the HIV LTR promoter. The present studies were undertaken to examine whether M4N is able to inhibit the replication of herpes simplex virus (HSV), another Sp1-regulated virus. The results showed that in Vero cells, M4N inhibits at micromolar levels (IC50 = 43.5 microM) the expression of the herpes immediate early gene (alpha-ICP4), which is essential for HSV replication. An electrophoretic mobility shift assay, examining Sp1 binding to the alpha-ICP4 promoter, showed a significant inhibition of the control bands: 88% inhibition of the fast moving band (FMB) and 45% of the slow moving band (SMB), at 100 microM of drug concentration. Comparative studies between M4N and acycloguanosine (acyclovir, ACV) in cultured Vero cells revealed an interesting pattern in the drug sensitivity (IC50) and cytotoxicity (TC50) parameters. For M4N, the IC50 varied between 11.7 and 4 microM in 10 passages of HSV-1 and 4 passages of HSV-2 with no indication for a requirement of higher drug concentration. In contrast, for acyclovir, the IC50 increased from 7 microM in the first passage to 444 microM in the tenth passage of HSV-1, and >88 microM for the fourth passage of HSV-2, indicating a rapid build-up of drug resistance against acyclovir. While the selective index (SI), defined as the ratio: TC50/IC50, remained relatively constant for M4N; it dropped 60-fold for acyclovir in the endpoints of viral passages. Drug sensitivity for M4N toward the acyclovir-sensitive strain (sm44) and the acyclovir-resistant strain (ACV-10) of HSV-1 was similar, indicating no cross-resistance between M4N and acyclovir in their anti-HSV effects. These results may have an important clinical relevance since HSV has been shown to be a factor for spreading of HIV.

Lobeline displaces [3H]dihydrotetrabenazine binding and releases [3H]dopamine from rat striatal synaptic vesicles: comparison with d-amphetamine

Lobeline, an alkaloid from Indian tobacco (Lobelia inflata), is classified as a nicotinic agonist and is currently used as a smoking cessation agent. However, our previous in vitro studies demonstrate that lobeline does not act as a nicotinic agonist but alters presynaptic dopamine (DA) storage by potently inhibiting DA uptake into synaptic vesicles. Recently, d-amphetamine has been reported to act at the level of the synaptic vesicle to alter presynaptic function. The present in vitro studies further elucidate the mechanism of lobeline's action and compare its effects with those of d-amphetamine. [3H]Dihydrotetrabenazine ([3H]DTBZ), used routinely to probe a high-affinity binding site on the vesicular monoamine transporter (VMAT2), bound to vesicle membranes from rat striatum with a KD of 1.67 nM and Bmax of 8.68 pmol/mg of protein. Lobeline inhibited [3H]DTBZ binding with an IC50 of 0.90 microM, consistent with its previously reported IC50 of 0.88 microM for inhibition of [3H]DA uptake into vesicles. These results suggest that lobeline specifically interacts with DTBZ sites on VMAT2 to inhibit DA uptake into synaptic vesicles. Interestingly, d-amphetamine inhibited [3H]DTBZ binding to vesicle membranes with an IC50 of 39.4 microM, a concentration 20 times greater than reported for inhibition of VMAT2 function, suggesting that d-amphetamine interacts with a different site than lobeline on VMAT2 to inhibit monoamine uptake. Kinetic analysis of [3H]DA release from [3H]DA-preloaded synaptic vesicles in the absence of drug revealed a t1/2 of 2.12 min. Lobeline and d-amphetamine evoked [3H]DA release with EC50 values of 25.3 and 2.22 microM, respectively. At a concentration 10 times the EC50, lobeline and d-amphetamine significantly decreased the t1/2 of [3H]DA release to 1.58 and 1.48 min, respectively. Thus, in contrast to d-amphetamine, which is equipotent in inhibiting DA uptake and promoting release from the synaptic vesicles, lobeline more potently (28-fold) inhibits DA uptake (via an interaction with the DTBZ site on VMAT2) than it evokes DA release to redistribute presynaptic DA storage.

Clinical experience with orbicularis oculi myocutaneous flaps in the temporal area

There are many methods to repair facial skin defects in clinical practice. The desired outcome for the surgeon and the patient is the restoration of facial appearance and function. The temporal region is one of the ideal donor sites for the repair of a facial skin defect, because this area is relatively inconspicuous and the skin quality is similar to that of the face. In the past, the temporal region was always used as the donor site of the local flap for repairing the facial skin defect. Because the blood supply of the skin comes from the subjacent tissue mainly rather than from the contiguous tissue, the pedicles of the local flaps are short, limiting the use of this area as a donor site. From 1993 to 1996, the anatomy of the orbicularis oculi myocutaneous flap in five cadavers was studied; what was learned allowed for the use of this flap to repair skin defects of the face in 13 patients. In this paper, the clinical experiences using the orbicularis oculi myocutaneous flaps to repair skin defects of the face and the surgical anatomy of this myocutaneous flap are discussed.

2/3 osteotomy for lengthening the mandible in dogs by gradual distraction

Successful lengthening of the mandible by gradual distraction has been reported previously. There are various methods for osteotomy before distraction osteogenesis. In this paper, a new type of osteotomy, performed on growing dogs as a model, is reported. Ten mongrel dogs, aged 6 months, were studied. A unilateral 2/3 osteotomy was performed, and an external lengthening device was fixed to the mandible perpendicular to the osteotomy. Seven days after the operation, the mandible was lengthened by 1 mm per day. The dogs were sacrificed for histological study at the end of the distraction on days 14, 28, 56 and 120 following completion of the distraction.

Nicotinic-receptor mediation of S(-)nornicotine-evoked -3H-overflow from rat striatal slices preloaded with -3H-dopamine

Previous results from our laboratory demonstrated that S(-)nornicotine, a major tobacco alkaloid and an active nicotine metabolite present in the CNS, increases dopamine release from rat striatal slices in a concentration-dependent and calcium-dependent manner. The present study determined if S(-)nornicotine-evoked dopamine release was the result of nicotinic receptor stimulation. Stereoselectivity and the ability of classical noncompetitive and competitive nicotinic receptor antagonists (mecamylamine (MEC) and dihydro-beta-erythroidine (DHbetaE), respectively) to inhibit S(-)nornicotine-evoked [3H]overflow from [3H]dopamine-preloaded rat striatal slices were investigated. Nornicotine increased [3H]overflow in a stereoselective manner at concentrations from 1 to 100 microM. MEC (0.01-100 microM) or DHbetaE (0.01-10 microM) alone did not evoke -3H-overflow. However, 100 microM DHbetaE evoked -3H-overflow, and therefore, was not used in experiments investigating antagonism of S(-)nornicotine's effect. MEC and DHbetaE inhibited S(-)nicotine- (10 microM) evoked [3H]overflow in a concentration-dependent manner. Concentrations of MEC (100 microM) and DHbetaE (10 microM) which maximally inhibited S(-)nicotine's effect were chosen for subsequent experiments determining inhibition of the effect of S(-)nornicotine (0.1 microM-3 mM). MEC and DHbetaE significantly inhibited the effect of low concentrations (<100 microM) of S(-)nornicotine; however, higher concentrations (>100 microM) of S(-)nornicotine were not inhibited by either nicotinic antagonist. Taken together, the results suggest that low concentrations of S(-)nornicotine stimulate nicotinic receptors to evoke the release of dopamine from dopaminergic presynaptic terminals. Thus, nornicotine, which acts as an agonist at neuronal nicotinic receptors, may contribute to the neuropharmacological effects of nicotine and tobacco use.

[Inhibition effect of p53 antisense RNA on malignant phenotype of colorectal cancer cells]

OBJECTIVE

Inhibition effect of p53 antisense RNA on malignant phenotype of colorectal cancer cells was studied.

METHODS

For the purpose of inhibiting tumorigenecity of mutant p53 gene in colorectal cancer cells, a 2.1 kb human p53 full length cDNA was inserted into a mammalian expression vector pREP9 to make a p53 antisense RNA expression vector pREP9-p53 (AS). pREP9-p53 (AS) was then introduced into human colorectal cancer cell line SW1116 (with mutated endogenous p53). MTT method and FCM analysis were performed to measure the effect of p53 antisense RNA expressed by pREP9-p53 (AS) on SW1116 cell cycle progression.

RESULTS AND CONCLUSION

It was shown that the growth rate of SW1116 cells with pREP9-p53 (AS) was significantly suppressed by the expression of p53 antisense RNA as compared to the control SW1116 cells and SW1116 cells with pREP9 vector alone. FCM analysis showed that SW1116 cells with pREP9-p53 (AS) were arrested at G0/1 phase, whereas no significant influence can be observed on control SW1116 cells with pREP9.

Lobeline and nicotine evoke [3H]overflow from rat striatal slices preloaded with [3H]dopamine: differential inhibition of synaptosomal and vesicular [3H]dopamine uptake

Lobeline is currently being developed as a substitution therapy for tobacco smoking cessation. Activation of CNS dopamine (DA) systems results in the reinforcing properties of nicotine. The present study compared the effects of lobeline and nicotine on rat striatum. Both lobeline and nicotine evoked [3H]overflow from striatal slices superfused in the presence of pargyline and nomifensine in the buffer. Marked DA depletion (42-67%) and a concomitant 2-fold increase in dihydroxyphenylacetic acid (DOPAC) in slices superfused with high concentrations (30-100 microM) of lobeline were observed. The effect of nicotine (10 microM) was inhibited in a concentration-dependent manner by mecamylamine (1-100 microM). However, lobeline (0.1-100 microM)-evoked [3H]overflow was calcium-independent, and was not antagonized by mecamylamine (1-100 microM), suggesting a mechanism of action other than stimulation of nicotinic receptors. Lobeline inhibited [3H]DA uptake into synaptosomes (IC50 = 80 +/- 12 microM) and vesicles (IC50 = 0.88 +/- 0.001 microM), whereas nicotine (< or =100 microM) did not inhibit synaptosomal or vesicular [3H]DA uptake. In the absence of pargyline and nomifensine in the buffer, endogenous DA was detected in superfusate only in those slices exposed to the highest concentration (100 microM) of lobeline. However, endogenous DOPAC concentration was increased in a concentration-dependent manner, indicating that lobeline exposure resulted in increased cytosolic DA which was rapidly metabolized to DOPAC. Under these conditions, lobeline (10-100 microM) also significantly depleted (66-85%) DA content; however, no change in DOPAC content was observed. The results suggest that, unlike nicotine, lobeline increases DA release by potent inhibition of DA uptake into synaptic vesicles, and a subsequent alteration in presynaptic DA storage.

Magnetic resonance imaging of the hepatobiliary system: intestinal absorption studies of manganese mesoporphyrin

RATIONALE AND OBJECTIVES

We studied the intestinal absorption of manganese mesoporphyrin (Mn-mesoporphyrin), a potential oral hepatobiliary contrast agent.

METHODS

Mn-mesoporphyrin was complexed with monoolein and taurocholate (mixed micelles). Portal venous delivery and biliary excretion were measured after intestinal administration in rats and rabbits, and the mechanism of intestinal transport was studied in a combined lymph-bile fistula model in rats. T1-weighted magnetic resonance (MR) images of the liver were obtained in rats and domestic pigs before and after gastric administration of Mn-mesoporphyrin in mixed micelles.

RESULTS

A 2.2-fold increase of portal venous Mn concentration was found 90 min after intestinal administration of the complex. None was found in the lymph collected from the thoracic duct, indicating a transcellular transport mechanism through the intestinal mucosa with portal venous delivery. Mn-mesoporphyrin levels in bile peaked between 240 and 270 min after administration (200-fold increase). The greatest liver enhancement (20-90%) was measured 360 min after administration.

CONCLUSION

The feasibility of intestinal delivery of Mn-mesoporphyrin, a lipophilic hepatobiliary contrast agent was demonstrated.

[Mentoplasty for common congenital mandibular deformities]

Since 1987, the authors have performed mentoplasty for congenital mandibular deformities in 46 patients with the assistance of X-ray pantomoscanning. Mandibular deformities include: 1) Bilateral hyperplasia of mandibular angles and massetter hypertrophy; 2) Retrognathia or micrognathia; 3) Asymmetric mandibular deformity. In this paper, following problems are discussed: 1) The advantages of an extraoral approach in mentoplasty; 2) The importance of the X-ray pantomoscanning; 3) The specific feature of asymmetric chin; 4) The improvement of the silicon implant used in mentoplasty; 5) Evaluation of the composite operative result.