[Relationship between myocardial microRNA-30a expression and myocardial fibrosis in rats post myocardial infarction]

OBJECTIVE

To explore the potential role and mechanism of microRNA(miR)-30a in myocardial fibrosis after myocardial infarction (MI).

METHODS

Rats were randomly divided into 1 week MI group (n=11), 2 weeks MI group (n=13) and 4 weeks MI group (n=15) by applying random number table after left anterior descending coronary artery ligation. Rats in Sham group were examined at respective time points (n=16). Heart function was monitored by echocardiography. Myocardial collagen volume fraction (CVF) was determined on Masson stained sections. Myocardial expression of collagen Ⅰ and Ⅲ was determined by immunohistochemistry. The myocardial mRNA level of miR-30a, TGF-β1 and CTGF were detected by real time-quantitative PCR analysis. The myocardial protein levels of TGF-β1 and CTGF were measured by Western blot analysis.

RESULTS

The LVEDD ((8.37±0.58) mm) and LVESD ((6.12±0.82) mm) in 4 weeks MI group were significantly higher than those in Sham group ((6.08±0.57) mm, (4.17±0.60) mm), all P<0.01. The FS ((27.0±3.9) %) and LVEF ((51.0±6.3) %) in 4 weeks MI group were significantly lower than those in Sham group ((47.0±2.1) %, (82.0±2.3)%), all P<0.01. The level of myocardial CVF in 1 week MI group, 2 weeks MI group and 4 weeks MI group were significantly higher than in Sham group (all P<0.01) in a time-dependent manner. The level of myocardial collagen Ⅰ and Ⅲ was increased gradually from 1 week to 4 weeks post MI compared with Sham group (all P<0.01). The collagen Ⅰ/Ⅲ ratio was similar between 1 week MI group and Sham group (P=0.58), however, which was significantly higher in 2 weeks MI group and 4 weeks MI group compared with Sham group (all P<0.01), and the ratio was significantly higher in 4 weeks MI group than 2 weeks MI group (P<0.01). The level of miR-30a was significantly and gradually reduced in all MI groups compared with Sham group (all P<0.01). The mRNA and protein levels of TGF-β1 and CTGF were significantly and gradually increased after MI compared with Sham group (all P<0.001).

CONCLUSIONS

Our results indicate that overexpression of miR-30a after MI might be a potential strategy for suppressing myocardial fibrosis by modulating the mRNA and protein levels of TGF-β1 and CTGF.

[The protective effect of regulation of paraoxonase 1 gene on liver oxidative stress injury induced by dichlorvos poisoning in mice]

OBJECTIVE

To investigate the protective effect of paraoxonase 1 (PON1) gene against liver oxidative stress injury in mice due to dichlorvos poisoning.

METHODS

Experiment 1: 12 male Balb/c mice were randomly divided into three groups, with 4 mice in each group: control group, green fluorescent protein lentivirus control group (Lv-GFP group), and recombinant PON1 lentivirus group (Lv-PON1 group). 2 × 10⁷ TU of Lv-GFP or Lv-PON1 was transfected via tail vein, while normal saline was given to those in control group. Blood was collected on 0, 1, 3, 5, 7, 9 days via fundus venous plexus for the assay of serum PON1 activity. PON1 mRNA and protein expression levels were respectively determined by reverse transcription-polymerase chain reaction (RT-PCR) and Western Blot on the 3rd post-lentivirus transfection day. Experiment 2: according to the random number table method, another 96 male Balb/c mice were divided into four groups of 24 mice in each control group, dichlorvos group, Lv-GFP intervention group, and Lv-PON1 intervention group. Lv-GFP or Lv-PON1 was transfected via tail vein followed by intraperitoneal injection of dichlorvos 9 mg/kg, while those in control group were given normal saline. Six mice in each group were sacrificed respectively at 6, 12, 24, 48 hours, and liver tissue was collected. PON1 mRNA and nuclear factor E2-related factor 2 (Nrf2) mRNA expression levels were determined by RT-PCR, and PON1 protein level was determined by Western Blot. The content of malondialdehyde (MDA) and glutathione (GSH) in the liver tissue were determined by chemical colorimetry. The activity of superoxide dismutase (SOD) and catalase (CAT) were measured by double antibody sandwich enzyme linked immunosorbent assay (ELISA).

RESULTS

Experiment 1: after Lv-PON1 was transfected to normal mice, PON1 activity in serum gradually increased and maintained a high level on 3rd day, while that of the control group and Lv-GFP group showed a normal low level. On the 3rd post-lentivirus transfection day, PON1 mRNA and PON1 protein expressions in liver were significantly higher than those of control group and Lv-GFP group. Experiment 2: compared with control group, the mice in dichlorvos group showed significant decreases in PON1 mRNA, PON1 protein, Nrf2 mRNA as well as GSH, SOD, CAT levels at 6 hours [PON1 mRNA (gray value): 0.237 ± 0.075 vs. 0.674 ± 0.011, PON1 protein (gray value): 0.602 ± 0.086 vs. 0.998 ± 0.124, Nrf2 mRNA (gray value): 0.089 ± 0.012 vs. 0.126 ± 0.010, GSH (mg/g): 3.84 ± 0.33 vs. 5.52 ± 0.40, SOD (μg/g): 0.383 ± 0.040 vs. 0.564 ± 0.052, CAT (ng/g): 7.32 ± 1.28 vs. 12.46 ± 1.54, all P < 0.05 ], and remarkable increase in MDA content (nmol/g: 7.78 ± 0.41 vs. 2.34 ± 0.25, P < 0.05). With the extension of time, PON1 mRNA, PON1 protein, Nrf2 mRNA and GSH, SOD, CAT levels gradually increased, MDA content gradually decreased, Nrf2 mRNA expression level had risen to the level of control group at 24 hours (0.133 ± 0.019 vs. 0.126 ± 0.009, P > 0.05), and it was higher than that of the control group at 48 hours ( 0.206 ± 0.028 vs. 0.124 ± 0.010, P < 0.05). Compared with that of the dichlorvos group, Lv-PON1 intervention group showed a significant increase in PON1 mRNA, PON1 protein, Nrf2 mRNA and GSH, SOD, CAT levels [PON1 mRNA (gray value): 0.726 ± 0.021 vs. 0.237 ± 0.075, PON1 protein (gray value): 0.739 ± 0.050 vs. 0.602 ± 0.086, Nrf2 mRNA (gray value): 0.158 ± 0.007 vs. 0.089 ± 0.012, GSH (mg/g): 4.30 ± 0.22 vs. 3.84 ± 0.33, SOD ( μg/g): 0.454 ± 0.062 vs. 0.383 ± 0.040, CAT (ng/g): 8.98 ± 1.02 vs. 7.32 ± 1.28, all P < 0.05 ], and a decrease in MDA content (nmol/g: 6.56 ± 0.44 vs. 7.78 ± 0.41, P < 0.05).

CONCLUSIONS

Regulation of PON1 gene can reduce MDA content, enhance SOD and CAT activities, increase GSH content, and it may also up-regulate Nrf2 mRNA expression to play a protective effect against oxidative stress of liver injury induced by dichlorvos poisoning.

Resveratrol protects mice from paraquat-induced lung injury: The important role of SIRT1 and NRF2 antioxidant pathways

Sirtuin 1 (SIRT1) acts via the deacetylation of a number of crucial transcription factors and has been implicated in various biological processes, including oxidative stress. Previous studies have indicated that nuclear factor, erythroid 2‑like 2 (NRF2) is an effective target of antioxidant therapy for paraquat (PQ) poisoning. However, the association between SIRT1 and NRF2 and their effects in PQ‑induced oxidative stress remains to be elucidated. The current study demonstrated that PQ exposure upregulated the expression of SIRT1 and NRF2 following 6‑ and 24‑h exposure in the lungs of mice. However, long‑term exposure to PQ significantly decreased the expression of SIRT1 and NRF2. Resveratrol is a SIRT1 activator, and strongly enhanced SIRT1 expression and attenuated the lung injury resulting from PQ exposure in the current study. Additionally, treatment with resveratrol upregulated the expression of NRF2 and glutathione, increased the activity of heme oxygenase‑1, superoxide dismutase and catalase, but depleted the expression of malondialdehyde. The present results demonstrated that resveratrol reduced PQ‑induced oxidative stress and lung injury, potentially through the positive feedback signaling loop between SIRT1 and NRF2.

An endurance-enhancing effect of peanut meal protein hydrolysate in mice: possible involvement of a specific peanut peptide

To improve the functional properties of peanut meal protein for wide utilization, hydrolysis was conducted by alcalase. Compared with saline and peanut meal protein, intragastric administration of low molecular weight (<1 kD) peanut meal peptide (PPH I) could significantly prolong swimming time, increase levels of blood sugar, non-esterified fatty acids (NEFA) and liver glycogen and decrease blood lactate content in mice. Levels of Pro, Leu, Val and His in low molecular weight peanut meal peptides were higher significantly than those in other peanut meal protein hydrolysates. Hydrophobic amino acids, such as Pro, Tyr and His, could perhaps capture free radical and increase antioxidant capacity of peanut peptide and retard fatigue induced by free radical. After separation by HPLC, a primary peptide P1, Pro-Glu-Ile-Glu-Val, was sequenced. Its N-terminal was Val, and it was rich in antioxidant amino acid, Pro and Ile. Levels of plasma glucose, NEFA and liver glycogen in PPH I group were higher than those in mice intragastric administration with peptide P1, and the swimming time is longer in PPH I group than in P1 group. So, the high content of P1 was one of the reason why PPH I had high endurance-enhancing capacity.

Establishment of an animal model of spontaneous cervical lymph node metastasis of laryngeal squamous cell carcinoma and obtaining laryngocarcinoma cells with high metastatic potential

To establish an animal model of spontaneous cervical lymph node metastasis of laryngeal squamous cell carcinoma and obtain laryngocarcinoma cells with high metastatic potential, laryngeal squamous cell carcinoma cell line HEP-2 in logarithmic phase were inoculated under the lingual margin mucosa of nude mice. HEP-2 cells metastasized to the cervical lymph nodes were isolated, cultured, and re-inoculated under the lingual margin mucosa of nude mice twice. The tumor formation in the tongue and in the cervical lymph nodes was confirmed by pathological examination. Carcinoma cells' ability of invasion and migration was detected by transwell assay. Human specific Alu sequences were detected by PCR, which indicated that the tumor cells originated from human laryngeal squamous cell carcinoma cell line HEP-2. Finally, an animal model of spontaneous lymph node metastasis of laryngeal squamous cell carcinoma was successfully established. Laryngeal squamous cell carcinoma cells with high metastatic potential to lymph nodes were obtained through repeated inoculations. .

Small interfering RNA specific for N-methyl-D-aspartate receptor 2B offers neuroprotection to dopamine neurons through activation of MAP kinase

In the present study, N-methyl-D-aspartate receptor 2B (NR2B)-specific siRNA was applied in parkinsonian models. Our previous results showed that reduction in expression of N-methyl-D-aspartate receptor 1 (NR1), the key subunit of N-methyl-D-aspartate receptors, by antisense oligos ameliorated the motor symptoms in the 6-hydroxydopamine (6-OHDA)-lesioned rat, an animal model of Parkinson's disease (PD).

Neuroprotective effects of neurokinin receptor one in dopaminergic neurons are mediated through Akt/PKB cell signaling pathway

Neurokinin one (NK1) receptor is Substance P (SP) receptor and it is abundantly distributed in the basal ganglia. Growing evidences were shown on their possible roles in the pathogenesis and treatment of Parkinson's disease (PD). NK1 receptor is a kind of G-protein-coupled-receptor (GPCR) and it links to various downstream survival signaling pathways. In the present study, treatment of NK1 receptor agonist septide [(Pyr6, Pro9)-SP (6-11)] was found to ameliorate the motor deficit in 6-hydroxydopamine (6-OHDA) lesioned rats in apomorphine rotation test. Septide treatments were also demonstrated to provide neuroprotection. In 6-OHDA lesioned rats, protection of TH immunoreactive neurons and terminals in substantia nigra (SN) and striatum was found after septide treatment. In SH-SY5Y cultures, cytotoxicity of 6-OHDA was reduced by septide pretreatment. In addition, up-regulations of phosphorylated serine-threonine kinase Akt and phosphorylated mitochondrial apoptotic protein BAD were observed in both in vivo and in vitro models, indicating the inhibition of apoptotic pathway by septide. In conclusion, septide could trigger the pro-survival Akt/PKB signaling pathway and protect dopaminergic neurons in in vivo and in vitro models against 6-OHDA toxicity. Therefore septide treatment may have therapeutic implications in treatment of PD.

The effect of microwave and bipolar radio-frequency ablation in the surgical treatment of permanent atrial fibrillation during valve surgery

BACKGROUND

Atrial fibrillation (AF) is a frequent problem in patients undergoing valve surgery. This study compared microwave and bipolar radio-frequency ablation of the left atrium in AF patients undergoing valve surgery.

METHODS

Patients who required left atrial ablation for permanent AF (duration > 6 months) during valve surgery were randomized to a microwave group (n = 94) or a radio-frequency group (n = 93). Regular follow-up was carried out at 3, 6, 9 and 12 months post-procedure and annually thereafter.

RESULTS

There were 4 postoperative deaths in the microwave group and 2 in the radio-frequency group. The median follow-up for all patients was 24.0 months (range: 12-36.0 months). Freedom from AF recurrence was significantly higher in the radio-frequency group than in the microwave group at 3 months (85.7 vs. 72.2 %, P = 0.026), 6 months (87.9 vs. 73.3 %%, P = 0.013), 9 months (84.6 vs. 68.9 %, P = 0.012), 12 months (84.6 vs. 67.8 %%, P = 0.008), and 24 months (88.7 vs. 71.2 %, P = 0.022) and at the latest follow-up (81.3 vs. 65.6 %, P = 0.016).

CONCLUSION

Bipolar radio-frequency ablation is superior to microwave ablation for the treatment of permanent AF in patients undergoing valve surgery.

Elucidating therapeutic effects on patients with hepatocellular carcinoma and main portal vein thrombosis

BACKGROUND/AIMS

The survival duration for patients diagnosed with hepatocellular carcinoma (HCC) with main portal vein thrombosis (MPVT) was usually less than 3 months. The aim of this study is to elucidate whether treatment can prolong the survival for such patients.

METHODOLOGY

Retrospectively we analyzed the clinical features and outcomes of 63 patients with HCC and MPVT over a 7-year period. Three therapeutic modalities--transcatheter arterial chemotherapy (TAC) with or without radiotherapy (RT), and systemic chemotherapy--were applied.

RESULTS

The patients were divided into two groups: 34 (54%) patients were treated, while the remaining 29 (46%) were not. Multivariate analysis revealed that Child-Pugh class, Okuda stage for HCC and the presence of treatment were the principal factors to predict survival. The survival was significantly longer in treated patients than those untreated both in the Child-Pugh class A or B patients. Significantly longer survival is evident in patients treated by TAC combing RT compared to those underwent TAC alone, systemic chemotherapy or no treatment.

CONCLUSIONS

The survival of Child-Pugh class A or B patients can be extended by the use of an appropriate therapeutic modality. TAC combined with RT did the best benefit to prolong survival in such patients.

[Application of the wavelet transform in terahertz time-domain spectroscopy]

With the development of ultrafast laser technique and deeper understanding of the terahertz (THz)electromagnetic wave, THz time domain spectroscopy (THz-TDS)has become a novel and rapidly developed technique. It has been applied in many fields such as biomedical diagnostics, semiconductor wafer diagnostics, and inspection of artwork However, the achieved spectrum will exhibit strong oscillations when it is measured in air environment due to the absorption of water vapor. In the present paper, spectra in the range of 0.2-1.9 THz for seven kinds of samples were measured by THz-TDs in both nitrogen and air environment. The wavelet transform was used to process the data measured in the air environment to eliminate the influence of water vapor. The feasibility of this method was demonstrated by the experimental results.

Early evidence of the genus Homo in East Asia

The timing and route of the earliest dispersal from Africa to Eastern Asia are contentious topics in the study of early human evolution because Asian hominin fossil sites with precise age constraints are very limited. Here we report new high-resolution magnetostratigraphic results that place stringent age controls on excavated hominin incisors and stone tools from the Yuanmou Basin, southwest China. The hominin-bearing layer resides in a reverse polarity magnetozone just above the upper boundary of the Olduvai subchron, yielding an estimated age of 1.7Ma. The finding represents the age of the earliest documented presence of Homo, with affinities to Homo erectus, in mainland East Asia. This age estimate is roughly the same as for H. erectus in island Southeast Asia and immediately prior to the oldest archaeological evidence in northeast Asia. Mammalian fauna and pollen obtained directly from the hominin site indicate that the Yuanmou hominins lived in a varied habitat of open vegetation with patches of bushland and forest on an alluvial fan close to a lake or swamp. The age and location are consistent with a rapid southern migration route of initial hominin populations into Eastern Asia.

Detection of human parvovirus B19 in papillary thyroid carcinoma

To evaluate whether parvovirus B19, a common human pathogen, was also involved in papillary thyroid carcinoma (PTC), 112 paraffin-embedded thyroid specimens of benign nodules, papillary, medullary and follicular carcinomas, and normal controls were examined for B19 DNA and capsid protein by nested PCR, in situ hybridisation (ISH) and immunohistochemistry (IHC). The expression of the nuclear factor-κB (NF-κB) was investigated by IHC. The results showed B19 DNA commonly exists in human thyroid tissues; however, there were significant differences between PTC group and normal controls, and between PTC and nonneoplastic adjacent tissues (P<0.001). The presence of viral DNA in PTC neoplastic epithelium was confirmed by laser-capture microdissection and sequencing of nested PCR products. B19 capsid protein in PTC group was significantly higher than that of all the control groups and nonneoplastic adjacent tissues (P⩽0.001). Compared with control groups, the activation of NF-κB in PTC group was significantly increased (P⩽0.02), except for medullary carcinomas, and the activation of NF-κB was correlated with the viral protein presence (P=0.002). Moreover, NF-κB was colocalised with B19 DNA in the neoplastic epithelium of PTC by double staining of IHC and ISH. These results indicate for the first time a possible role of B19 in pathogenesis of PTC.

Up-regulation in expression of vesicular glutamate transporter 3 in substantia nigra but not in striatum of 6-hydroxydopamine-lesioned rats

Overactivity of the glutamatergic system is suggested to be closely related to the onset and pathogenesis of Parkinson's disease. Vesicular glutamate transporters (VGLUT1, T2 and T3) are a group of glutamate transporters in neurons that are responsible for transporting glutamate into synaptic vesicles and they are key elements for homeostasis of glutamate neurotransmission. The present study was aimed to investigate the expression of VGLUT1, T2 and T3 proteins after the onset of Parkinson's disease. A rat model of Parkinson's disease, the 6-hydroxydopamine-lesioned rat, was employed. Immunocytochemistry revealed that VGLUT1, T2 and T3 immunoreactivity was not modulated in the striatum of the lesioned rat. Western blotting analyses also showed that there was no change in the expression of T1, T2 and T3 proteins in the striatum. In contrast, no VGLUT1 protein was detected in the substantia nigra. After the lesion, levels of VGLUT2 immunoreactivity and protein were not modulated. Significant increase of VGLUT3 immunoreactivity was observed in the perikarya of GABAergic substantia nigra pars reticulata neurons (+14.7%) although VGLUT3 protein was not modulated in the nigral tissues. VGLUT3 in GABAergic neurons is suggested to play a role in GABA synthesis. The present results may therefore implicate that VGLUT1 and T2 are not modulated in the striatum and the substantia nigra of the 6-hydroxydopamine-lesioned rat and only VGLUT3 plays a role in pathogenesis of Parkinson's disease.

Ablation of gene expression of N-methyl-D-aspartate receptor one by antisense oligonucleotides in striatal neurons in culture

In the present study, a twenty-mer antisense oligonucleotide specific for N-methyl-D-aspartate receptor one (ANR1) was applied to striatal neurons in primary cell culture. The ANR1 was found to be specific and nontoxic. Significant reductions in expression of NR1 mRNA and proteins were resulted after a single dose of ANR1 transcripts. Interestingly, there were reductions in total NR1 proteins but two phosphorylated forms of NR1 proteins at serine 896 and 897 residues were not reduced. There was also no change in the pattern of distribution of NR1 immunoreactivity in the striatal neurons. In addition, significant reductions of NMDA-mediated peak inward current were found after application of a higher concentration of ANR1 (20-100 microM) by patch clamp recordings. The present results indicate that ANR1 is a useful agent in reducing NMDA receptor functions. The present data thus provide detailed cellular and molecular mechanisms to explain our previous findings of amelioration of motor symptoms in a rat model of Parkinson's disease. More importantly, application of ANR1 was also found to display neuroprotective effects of striatal neurons against NMDA-induced excitotoxic cell death. The findings have implications in development of new approach in prevention of cell death in neurodegenerative diseases and new treatments for these diseases.

Splenic tumour: a clinicopathological study

Splenic tumours are occasionally found during routine physical check-ups or elective abdominal image studies. Histologically, most splenic tumours are of benign vascular origin. To avoid unnecessary surgery for asymptomatic patients with benign splenic tumours and clarify the clinicopathological features of spleen tumours, this study gathered 44 cases of primary or isolated metastatic spleen tumours confirmed by pathology from surgery specimens or biopsies. The differences in clinicopathological features and image presentations between benign and malignant spleen tumour were investigated. Thirty-two cases involved benign tumours while 12 cases were malignant. Among the benign tumours, vascular originating tumours were most common (with 14 cases of cavernous haemangiomas, 13 cases of lymphangioma, three cases of lymphangiohaemangioma and one case of Littoral cell angioma). Notably, one, case of inflammatory pseudotumour because of Schistosoma parasite infection was also noted. Among the malignant tumours, there were four cases of angiosarcomas with vascular endothelium origins, as well as lymphomas and six metastatic tumours. Image studies were non-specific. Image study alone is an inadequate basis for making differential diagnoses between benign and malignant tumours. Instead, pathological studies are required for a final diagnosis. Using previous studies and this investigation, fine needle aspiration biopsy of spleen tumours with the help of ultrasonic or computed tomography appears a safe and effective method for obtaining biopsy specimens. Splenectomy is recommended only for patients with malignancies or complications such as intractable abdominal pain, coagulopathy or tumour rupture with an unstable haemodynamic state.

Neurokinin peptides and neurokinin receptors as potential therapeutic intervention targets of basal ganglia in the prevention and treatment of Parkinson's disease

Parkinson's disease (PD) is a serious motor disorder and it is the second most common brain degenerative disease in human. PD is known to be caused by degeneration of dopamine neurons in the substantia nigra but the cause of cell death is largely unknown. Mammalian neurokinins [NKs] are a group of neuropeptides that include substance P (SP; neurokinin-1, NK-1), substance K (SK; NK-2; neurokinin A), and neuromedin K (NK; NK-3; neurokinin B). Their biological effects as neurotransmitters, neuromodulators, or neurotrophic-like factors are mediated by three distinct neurokinin receptors, namely SP receptor (SPR: NK-1 receptor, NK-1R), SKR (NK-2R), and NKR (NK-3R). Several lines of evidence have indicated that neurokinins are implicated in the pathogenesis of PD. First, decreases of SP level and SP-immunoreactivity have been found in nigral and striatal tissues of animals with PD and postmortem PD patients. Second, NKs exert neuroprotective effects on neurons. In addition, NK receptors, namely NK-1 and NK-3 receptors, are abundantly localized in dopaminergic and cholinergic neurons of the basal ganglia, indicating that these neurons are under the physiological regulation of NKs. Moreover, modulation in motor activity occurred in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice, PD animal model, after systemic administration of NK receptor agonists. NKs and NK receptors, therefore, might be important molecules that are associated with functions and survival of neurons in the basal ganglia, in particular the dopamine neurons. Further studies should be devoted to elucidate the functional roles of NK systems in (a) the neuropathogenesis and neuroprotection during the course of PD, (b) the efficacy of NK receptor drugs towards PD, and (c) potential therapeutic intervention that targets at the prevention or treatment of PD.

Receptors of glutamate and neurotrophin in vestibular neuronal functions

The last decade has witnessed advances in understanding the roles of receptors of neurotrophin and glutamate in the vestibular system. In the first section of this review, the biological actions of neurotrophins and their receptors in the peripheral and central vestibular systems are summarized. Emphasis will be placed on the roles of neurotrophins in developmental plasticity and in the maintenance of vestibular function in the adult animal. This is reviewed in relation to the developmental expression pattern of neurotrophins and their receptors within the vestibular nuclei. The second part is focused on the functional role of different glutamate receptors on central vestibular neurons. The developmental expression pattern of glutamate receptor subunits within the vestibular nuclei is reviewed in relation to the potential role of glutamate receptors in regulating the development of vestibular function.

Differential expression of AMPA receptor subunits in dopamine neurons of the rat brain: a double immunocytochemical study

We have examined the distribution of dopamine neurons expressing alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptor subunits (glutamate receptors 1, 2/3 and 4) in the A8-A15 regions of the rat brain using double immunofluorescence. The distribution of glutamate receptor 1- or 2/3-like immunoreactive neurons completely overlapped that of tyrosine hydroxylase-like immunoreactive neurons in dopamine cell groups in the retrorubral field (A8), the substantia nigra (A9), the ventral tegmental area and the nucleus raphe linealis (A10), and the rostral hypothalamic periventricular nucleus (A14, A15). In the caudal hypothalamic periventricular nucleus (A11), arcuate nucleus (A12) and zona incerta (A13), the distribution was partially overlapping. Neurons double-labeled for tyrosine hydroxylase and glutamate receptor 1 or 2/3 immunoreactivities were, however, exclusively found in certain dopamine cell regions: in areas A14-A15, 85-88% of tyrosine hydroxylase-containing neurons expressed glutamate receptor 1 and 22-25% expressed glutamate receptor 2/3, while in areas A8-A10, 20-43% expressed glutamate receptor 1 and 63-84% expressed glutamate receptor 2/3. In contrast, the double-labeled neurons were hardly detected in the A11-A13 regions. No tyrosine hydroxylase-positive neurons displayed glutamate receptor 4 immunoreactivity, though a partially overlapping distribution of tyrosine hydroxylase- and glutamate receptor 4-immunopositive neurons was also seen in regions A8-10, A11 and A13. The present study has demonstrated the morphological evidence for direct modulation of dopamine neurons via AMPA receptors in rat mesencephalon and hypothalamus. This distribution may provide the basis for a selective dopamine neuron loss in neurodegenerative disorders, such as Parkinson's disease.

Effect of neuropsychiatric symptoms of Alzheimer's disease on Chinese and American caregivers

BACKGROUND

In Chinese culture, extended family support, acceptance of age-related cognitive changes and filial tradition of caring for elders may decrease caregiver burden and distress in the context of dementia.

OBJECTIVE

To study cross-regional and cross-cultural differences in symptom-related caregiver distress due to the behavioral problems of Chinese and American patients with Alzheimer's disease.

METHOD

Caregivers of patients with Alzheimer's disease at Taipei Veterans General Hospital, Taiwan (n = 89), Chinese University of Hong Kong (n = 31) and the UCLA Alzheimer's Disease Research Center, Los Angeles, California (n = 169) reported the neuropsychiatric symptoms of patients and their corresponding distress on the Neuropsychiatric Inventory.

RESULT

Presence or absence of distress due to the neuropsychiatric symptoms of the patients with Alzheimer's disease was assessed. The three centers differed significantly in the proportions of caregivers with distress caused by depression (p < 0.05) and apathy (p < 0.001). UCLA had higher proportions of caregivers with depression-related distress than Taipei. UCLA caregivers were also more stressed by apathy than caregivers in Taipei and Hong Kong. Logistic regression further supported the findings that depression-related and apathy-related caregiver distress differed between Chinese and American caregivers (p < 0.05).

CONCLUSIONS

The results were surprising, in that American and Chinese (Taipei and Hong Kong) caregivers exhibited similar distress or lack of distress in response to delusions, hallucinations, agitation, anxiety, euphoria, disinhibition, irritability, aberrant motor behavior, sleep and appetite symptoms of Alzheimer's disease patients. Chinese caregivers were less affected by depression and apathy in patients with Alzheimer's disease than Caucasian caregivers.

Reactivation of hepatitis C virus superinfection in a patient seropositive for hepatitis B e antigen

During the course of chronic hepatitis B virus (HBV) infection, a patient seropositive for hepatitis B e antigen experienced four episodes of acute hepatic necroinflammation. Serum HBV-DNA concentration elevated immediately before the first and third exacerbations, whereas serum hepatitis C virus (HCV) RNA was detected during the second and fourth exacerbations. The nucleotide sequences of HCV hypervariable region derived from samples of the two exacerbations were identical. Interestingly, "de novo" seroconversion of anti-HCV antibody (Abbott HCV EIA 3.0) followed by reversion occurred in both the second and fourth exacerbations with low sample/cutoff ratios. Immunoblot analysis using a line-immunoassay (Inno-LIA HCV Ab III) revealed a single positive band (C1) developing after the second exacerbation. These data indicate that the second exacerbation in this patient was caused by newly acquired acute HCV superinfection, whereas the fourth exacerbation was likely due to reactivation of the previous HCV infection. Recognition of such a case suggests that the presence of de novo seroconversion of anti-HCV may indicate either reactivation or acute superinfection of HCV in a patient seropositive for hepatitis B e antigen.

Analysis of binding domain and function of chimeric mu/kappa opioid receptors to ohmefentanyl stereoisomers

AIM

To investigate specific domains in mu opioid receptors that accounted for selective binding of three stereoisomers of ohmefentanyl (Ohm9204, Ohm9202, and Ohm9203) and study the function of chimera II.

METHODS

Rat mu and kappa opioid receptors (RMOR, RKOR) and four mu/kappa chimeric receptors (chimeras) I, II, III, and IV were transiently expressed in COS-1 cells. The binding ability and binding domain of receptor to ligands were determined by radioactive ligand and receptor binding experiments. Through measuring cellular cAMP levels, we studied the function of chimera II in mediating signal transduction.

RESULTS

Binding affinities of four chimeric receptors were similar to wild type opioid receptors (RMOR and RKOR). The binding affinities of Ohm9204 and Ohm9202 to chimera II were similar to that of RMOR. The binding affinities of Ohm9203 to all six receptors were low. U50488 possessed high binding affinity to chimera I, however dynorphie A(1-9) had some binding affinity to chimera II that was similar to RKOR, which indicated the domains of RKOR accounting for selectively binding to peptide ligand dynorphie A(1-9) and nonpeptide ligand U50488 were different. The efficacy of Ohm9204 and Ohm9203 on inhibiting forskolin-stimulated cAMP accumulation in cells transfected with chimera II was similar to that in cells transfected with RMOR.

CONCLUSION

Replacing 194-268 residues of RMOR with 185-262 residues of RKOR does not influence the ability of mu opioid receptor to bind Ohm9204 and Ohm9202 and the receptor mediated inhibition of cellular cAMP level.

Mechanisms and modulation of formyl-methionyl-leucyl-phenylalanine (fMLP)-induced Ca2+ mobilization in human neutrophils

The effect of fMLP (N-formyl-methionyl-leucyl-phenylalanine), a neutrophil-stimulating bacterial peptide, on Ca2+ mobilization in human neutrophils was examined using fura-2 as a Ca2+ indicator. fMLP (10 nM-10 microM) increased [Ca2+]i concentration-dependently. The [Ca2+]i signal comprised an initial rise followed by a gradual decay and a sustained phase. External Ca2+ removal partly decreased the signal. La3+ (50 microM) pretreatment mimicked the effect of Ca2+ removal. In Ca(2+)-free medium, pretreatment with 1 microM thapsigargin (an endoplasmic reticulum Ca2+ pump inhibitor) prevented 10 microM fMLP from increasing [Ca2+]i; whereas 1 microM thapsigargin still significantly increased [Ca2+]i after pretreatment with 10 microM fMLP. Addition of 3 mM Ca2+ induced a concentration-dependent [Ca2+]i increase after pretreatment with fMLP in Ca(2+)-free medium. This Ca2+ entry was partly inhibited by econazole (25 microM), SKF96365 (50 microM), and a phospholipase A2 inhibitor (aristolochic acid; 20 microM). The fMLP (10 microM)-induced Ca2+ release was abolished by inhibiting phospholipase C with 2 microM U73122. The fMLP-induced [Ca2+]i increase was inhibited by 25% by pretreatment with 10 nM phorbol ester to activate protein kinase C but was augmented by 27% by pretreatment with 2 microM GF 109203X to inactivate protein kinase C. We found that fMLP increase reactive oxygen intermediate (ROI) production in neutrophils, which can be suppressed by U73122 pretreatment. Collectively, this study shows that in human neutrophils, fMLP increased [Ca2+]i concentration-dependently by releasing Ca2+ from phospholipase C-coupled, thapsigargin-sensitive stores, accompanied by Ca2+ entry. The fMLP-induced [Ca2+]i rise was modulated by protein kinase C, and the fMLP-induced Ca2+ entry was abolished by La3+, and was reduced by econazole, SKF96365 and inhibition of phospholipase A2.

Cholinergic neurons expressing neuromedin K receptor (NK3) in the basal forebrain of the rat: a double immunofluorescence study

By using a double immunofluorescence method we have examined the distribution of cholinergic neurons expressing neuromedin K receptor (NK3) in the rat brain and spinal cord. The distribution of neuromedin K receptor-like immunoreactive neurons completely overlapped with that of choline acetyltransferase-positive neurons in certain regions of the basal forebrain, e.g. the medial septal nucleus, nucleus of the diagonal band of Broca, magnocellular preoptic nucleus and substantia innominata. Partially overlapping distributions of neuromedin K receptor-like immunoreactive and choline acetyltransferase-positive neurons were found in the basal nucleus of Meynert, globus pallidus, ventral pallidum of the forebrain, tegmental nuclei of the pons and dorsal motor nucleus of the vagus. Neurons showing both neuromedin K receptor-like and choline acetyltransferase immunoreactivities, however, were found predominantly in the medial septal nucleus, nucleus of the diagonal band of Broca and magnocellular preoptic nucleus of the basal forebrain: 66-80% of these choline acetyltransferase-positive neurons displayed neuromedin K receptor-like immunoreactivity. Neurons showing both neuromedin K receptor-like and choline acetyltransferase immunoreactivities were hardly detected in other aforementioned regions of the forebrain, brainstem and spinal cord. The present study has provided morphological evidence for direct physiological modulation or regulation of cholinergic neurons by tachykinins through the neuromedin K receptor in the basal forebrain of rats.

Cholinergic neurons expressing substance P receptor (NK(1)) in the basal forebrain of the rat: a double immunocytochemical study

Cholinergic neurons expressing substance P receptor (SPR, NK(1)) were examined in the rat brain using double immunofluorescence. The distribution of SPR-like immunoreactive (SPR-LI) neurons completely overlapped with that of choline acetyltransferase (ChAT)-LI neurons in the medial septal nucleus, the nucleus of diagonal band of Broca, the magnocellular preoptic nucleus, the substantia innominata of basal forebrain, the caudate-putamen, and the ventral pallidum of the basal ganglia. In the mesopontine tegmentum and the cranial motor nuclei of the brainstem, the distribution of SPR-LI and ChAT-LI neurons was partially overlapping. Neurons showing both SPR-like and ChAT-like immunoreactivities, however, were predominantly found above basal forebrain regions and 82-90% of these ChAT-LI neurons displayed SPR-like immunoreactivity, in addition to the confirmatory observation that 100% of the ChAT-LI neurons exhibit SPR-like immunoreactivity in the basal ganglia. In contrast, neurons double-labeled for SPR-like and ChAT-like immunoreactivities were hardly detected in aforementioned regions of the brainstem. The present study has provided morphological evidence for direct physiological modulation of cholinergic neurons by tachykinins through substance P receptor in the basal forebrain of the rat.

Effect of the antianginal drug bepridil on intracellular Ca2+ release and extracellular Ca2+ influx in human neutrophils

To understand more fully the effects of bepridil, an antiarrhythmic and antianginal drug, on myocardial ischemia-reperfusion injury and systemic immune responses, its effect on intracellular Ca2+ levels ([Ca2+]i) in human neutrophils was investigated by using fura-2 as a fluorescent probe. Bepridil (10-200 microM) increased [Ca2+]i in a concentration-dependent fashion. This signal was partly inhibited by removal of extracellular Ca2+. In a Ca(2+)-free medium, pretreatment with bepridil (100 microM) abolished the Ca2+ release induced by thapsigargin (1 microM), an endoplasmic reticulum Ca2+ pump inhibitor, and by carbonylcyanide m-chlorophenylhydrazone (2 microM), a mitochondrial uncoupler. Pretreatment with carbonylcyanide m-chlorophenylhydrazone and thapsigargin, respectively, partly inhibited bepridil-induced Ca2+ release. Addition of Ca2+ (3 mM) increased [Ca2+]i after pretreatment with bepridil (100 microM) in a Ca(2+)-free medium. Bepridil (100 microM)-induced Ca2+ release was not altered when phospholipase C was inhibited by U73122 (2 microM). Both Ca2+ release and Ca2+ entry induced by bepridil (100 microM) were augmented by activating protein kinase C with phorbol 12-myristate 13-acetate (10 nM), and were suppressed by inhibiting protein kinase C with GF 109203X (2 microM). Treatment with bepridil (10-20 microM) for 30 min increased the production of reactive oxygen intermediates (ROI) by more than 50%. Collectively, it was found that bepridil increased [Ca2+]i concentration-dependently in human neutrophils by releasing Ca2+ from the endoplasmic reticulum, mitochondria and, possibly, other compartments in a phospholipase C-independent manner. Bepridil also activated Ca2+ influx. The activity of protein kinase C may regulate bepridil-induced Ca2+ release and Ca2+ entry.