[Exploration of phase angle used to construct PG-SGA nutritional assessment and prediction model for malignant tumor patients]

Objective: To explore the value of phase angle (PA) in constructing a predictive model of nutrition evaluation for tumor patients. Methods: A retrospective analysis was performed on 1 129 patients with malignant tumors hospitalized in the Cancer Center of Changzhi People's Hospital from June 2020 to February 2021. PA values of six parts of the body were measured by the body composition analyzer, including: left arm (LA), right arm (RA), left leg (LL), right leg (RL), the trunk (TR), and the whole body (WB). Patients' body mass index (BMI) was calculated and patient-generated subjective global assessment (PG-SGA) was assessed. The differences of PA values of six parts were compared and their correlations with BMI and PG-SGA in combination with age, gender and tumor disease types were analyzed, binary classification regression on BMI and PG-SGA was performed, and the functions of the best prediction model was fitted. Decision tree, random forest, Akaike information criterion in a Stepwise Algorithm (stepAIC) and generalized likelihood ratio test were used to select appropriate variables, and the logit logistic regression model was used to fit the data. Results: Comparing the PA values of six parts in pairs, it was found that the PA values of LA and RA, LL and RL, and TR and WB were linearly correlated and the coefficient was close to 1 (P<0.001). Binary classification regression was performed for BMI and PG-SGA, respectively. In order to make the data have clinical significance, 18.5 kg/m(2) was used as the classification point for BMI, 4 and 9 were used as the classification points for PG-SGA score, and the models of A, B and C were obtained. Suitable variables including PA-LA, PA-TR and tumor disease types were used as variables to fit BMI classification; BMI, PA-LA and age were used as variables to fit the PG-SGA model with 9 as the classification point. PA-LA, PA-TR, BMI, age and tumor disease types were used as variables to fit the PG-SGA model with 4 as the classification point. In this study, the predicted values of models A, B and C obtained by R-studio were imported into SPSS 26.0 software, and the cut-off values of classification were obtained by the receiver operating characteristic (ROC) curve. The ROC analytic results showed that the best cut-off values of Model A, B and C were 0.155, 0.793 and 0.295. Model A recommended when the probability is >0.155, a patient's nutritiond tatus should be classified as BMI < 18.5 kg/m(2) group. Model B recommended that PG-SGA<9 group be classified as the probability is >0.793. Model C recommended that PG-SGA < 4 group should be classified when probability is >0.295. Conclusions: The PG-SGA classification prediction model is simple to operate, and the nutritional status of patients can be roughly divided into three groups: normal or suspected malnutrition group (PG-SGA<4), moderate malnutrition group (4≤PG-SGA<9), and severe malnutrition group (PG-SGA≥9). This model can more efficiently predict the nutritional status of cancer patients, greatly simplify the nutritional assessment process, and better guide the standardized treatment of clinical malnutrition.

[Hepatic cystic echinococcosis complicated with tuberculous empyema misdiagnosed as hepatic and pulmonary cystic echinococcosis: one case report]

Hepatic cystic echinococcosis is a chronic parasitic disease caused by the infection with the larvae of Echinococcus granulosus in human or animal liver tissues. As a chronic active infectious disease, tuberculous empyema mainly invades the pleural space and then causes visceral and parietal pleura thickening. It is rare to present comorbidity for hepatic cystic echinococcosis and tuberculous empyema. This case report presents a case of hepatic cystic echinococcosis complicated with tuberculous empyema misdiagnosed as hepatic and pulmonary cystic echinococcosis, aiming to improve clinicians' ability to distinguish this disorder.

[Effects of perioperative transfusion of blood components on the long-term prognosis of hepatocellular carcinoma]

Objective: To investigate the effects of perioperative transfusion of blood components on the long-term prognosis of hepatocellular carcinoma (HCC) patients. Methods: A total of 339 patients with primary HCC who underwent curative hepatectomy between January 2003 and December 2010 at the Cancer Hospital, Chinese Academy of Medical Sciences were enrolled. The clinical data of the patients were retrospectively analyzed. These patients were divided into non-transfusion, fresh frozen plasma (FFP) transfusion only and concentrated red cells (CRC) transfusion groups. Disease-free survival and overall survival were estimated using the Kaplan-Meier method, and Cox regression was performed to identify clinicopathological factors related with survival. Results: Among the 339 patients, the 1-, 3- and 5-year disease-free survival rates were 63.1%, 35.4% and 22.4%, respectively, and the median disease-free survival was 22 months. While the 1-, 3- and 5-year overall survival rates were 90.5%, 69.5% and 56.4%, respectively, and the median overall survival was 72 months. The median disease-free survivals of the non-transfusion (n=181), FFP transfusion only (n=48) and CRC transfusion (n=110) groups were 28, 22 and 12 months, respectively, while the median overall survivals of the three groups were 99, 63 and 40 months respectively. Significant differences in the disease-free and overall survivals were observed among the three groups (both P<0.01). Multivariate Cox regression analyses showed that FFP transfusion only (HR=1.658, P=0.026), CRC transfusion (HR=1.470, P=0.030), serum alpha-fetoprotein>400 μg/L (HR=1.686, P=0.002), albumin<35 g/L (HR=1.782, P=0.047), tumor capsule (HR=0.597, P=0.012), tumor necrosis (HR=1.820, P=0.001) and the TNM stage Ⅲ or above (HR=2.537, P=0.000) were independent predictors of overall survival after hepatectomy. Conclusion: Both perioperative FFP only transfusion and CRC transfusion may have detrimental effect on the long-term prognosis of HCC.

First Report of Streptomyces galilaeus Associated with Common Scab in China

During a survey of potato scab pathogens in China from 2003 to 2012, a new pathogen was found in Shanxi and Neimenggu provinces. The incidence was approximately 20% of all recovered strains. The lesions caused by the pathogen were slightly raised and similar to those caused by Streptomyces scabies (3). Lesions were excised (approximately 10 mm³) from 40 infected tubers, surface-disinfested with 0.3% NaOCl for 30 s, rinsed in sterile water three times, cut into 5 mm³, then sliced into 1-mm pieces, and plated on water agar amended with ampicillin (50 μg/ml). Plates were incubated at 28°C in the dark for 4 days. The spores of Streptomyces sp. strains growing from the tuber pieces were collected from single bacterial colonies and cultured on oatmeal agar. To fulfill Koch's postulates, one strain, CPS-2, was grown at 28°C for 10 days and the spores were washed from the plates as inoculum. One hundred milliliters of inoculum (1 × 10⁵ CFU/ml) was mixed with autoclaved soil and vermiculite (1:1) in each pot (15 cm in diameter). Cut tubers were planted in the pots (potato cv. Favorita, one plant per pot, five replicates) and grown under greenhouse conditions (22 ± 5°C). Typical common scab symptoms consisting of small, brown, raised lesions developed on potato tubers 12 weeks after planting. The same strain was re-isolated from the lesions of the new scabby tubers. Non-inoculated plants, treated as described above, but without strain CPS-2, remained healthy. The CPS-2 strain was identified based on morphological and physiological characterization and 16S rDNA sequence. On yeast-malt extract agar, the test strain produced grayish-white aerial hypha, reddish brown substrate mycelium and pigments, and loose spiral spore chains. Spores were smooth and were 0.8 to 0.9 × 1.1 to 1.2 μm in size (diameter and length). The ability of the strain to use single sources of carbon and nitrogen was verified according to the International Streptomyces project (4). The strain grew in media supplemented with L-arabinose, D-fructose, D-glucose, rhamnose, raffinose, meso-inositol, sucrose, and D-xylose, but not D-mannitol. It used L-hydroxyproline, L-methionine, and L-histidine, and produced melanin on tyrosine and peptone yeast extract agar. The strain did not grow at a pH less than 5.0 and was sensitive to streptomycin (20 μg/ml), phenol (0.1%), and crystal violet (0.5 μg/mL), but not to penicillin (10 IU/ml). The strain also produced hydrogen sulfide. The biological characteristics of strain CPS-2 were in accord with Streptomyces galilaeus. CPS-2 produced thaxtomin A in oatmeal liquid medium and the txt AB gene fragment was successfully amplified using specific primers (2). The 16S rDNA sequence of CPS-2 was amplified by PCR with primers 16S1-F: 5'-CATTCACGGAGAGTTTGATCC-3' and 16S1-R: 5'-AGAAAGGAGGTGATCCAGCC-3' (1) and sequenced. A BLAST search of the 16S rDNA sequence for CPS-2 was conducted using the NCBI GenBank database, resulting in 99.8% similarity to S. galilaeus (NR_040857). The 16S rDNA sequence for CPS-2 (1,388 bp) was deposited in GenBank (AY621378). To our knowledge, this is the first report of S. galilaeus causing common scab of potato in China. References: (1) R. A. Bukhalid et al. Appl. Environ. Microbiol. 68:738, 2002. (2) R. Flores-González et al. Plant Pathol. 57:162, 2008. (3) D. H. Lambert and R. Loria. Int. J. Syst. Bacteriol. 39:387, 1989. (4) E. B. Shirling and D. Gottlieb. Int. J. Syst. Bacteriol. 16:313, 1966.

Protective effect of ischaemic preconditioning in total knee arthroplasty

OBJECTIVE

To investigate the genomic response induced by ischaemic preconditioning (IPC) in muscle biopsies taken from the operative leg of total knee arthroplasty patients.

MATERIALS AND METHODS

The gene expression profile GSE21164 was extracted from Gene Expression Omnibus (GEO) database. Patients undergoing primary knee arthroplasty were randomized to control and treatment (IPC) groups. Muscle biopsies were taken from the quadriceps muscle of the operative knee at the immediate onset of surgery (T0) and at 1 hour into surgery (T1). Limma package of R language was used to identify the differentially expressed genes (DEGs) between control and treatment group. To find out specific genes, DEGs at T0 were compared with DEGs at T1. Scansite was used to find out the binding domain for specific DEGs. Functional enrichment analysis was done by DAVID.

RESULTS

Of the genes queried on the Affymetrix Human Genome U133 Plus 2.0 microarray, we identified 263 (T0) and 266 (T1) DEGs compared to the control group. Down-regulation of DEGs related with regulation neuron apoptosis was observed at T1. The most significant function of DEGs at T0 was related with neurological system process. The most specific DEG was FAM125B at T0 and T1 time points. Its common binding domain was SH3.

CONCLUSIONS

The protective effect of IPC was associated with altered expression of genes involved in neurological system process and regulation of neuron apoptosis. The dynamic expression of FAM125B can be a supervised marker during the surgery. IPC may be of potential benefit in this and other musculoskeletal conditions.

Disruption of neocortical histone H3 homeostasis by soluble Aβ: implications for Alzheimer's disease

Amyloid-β peptide (Aβ) fragment misfolding may play a crucial role in the progression of Alzheimer's disease (AD) pathophysiology as well as epigenetic mechanisms at the DNA and histone level. We hypothesized that histone H3 homeostasis is disrupted in association with the appearance of soluble Aβ at an early stage in AD progression. We identified, localized, and compared histone H3 modifications in multiple model systems (neural-like SH-SY5Y, primary neurons, Tg2576 mice, and AD neocortex), and narrowed our focus to investigate 3 key motifs associated with regulating transcriptional activation and inhibition: acetylated lysine 14, phosphorylated serine 10 and dimethylated lysine 9. Our results in vitro and in vivo indicate that multimeric soluble Aβ may be a potent signaling molecule indirectly modulating the transcriptional activity of DNA by modulating histone H3 homeostasis. These findings reveal potential loci of transcriptional disruption relevant to AD. Identifying genes that undergo significant epigenetic alterations in response to Aβ could aid in the understanding of the pathogenesis of AD, as well as suggesting possible new treatment strategies.

Anti-N-methyl-D-aspartate receptor encephalitis with serum anti-thyroid antibodies and IgM antibodies against Epstein-Barr virus viral capsid antigen: a case report and one year follow-up

Background

Anti-N-methyl-D-aspartate receptor encephalitis is an increasingly common autoimmune disorder mediated by antibodies to certain subunit of the N-methyl-D-aspartate receptor. Recent literatures have described anti-thyroid and infectious serology in this encephalitis but without follow-up.

Case presentation

A 17-year-old Chinese female patient presented with psychiatric symptoms, memory deficits, behavioral problems and seizures. She then progressed through unresponsiveness, dyskinesias, autonomic instability and central hypoventilation during treatment. Her conventional blood work on admission showed high titers of IgG antibodies to thyroglobulin, thyroid peroxidase and IgM antibodies to Epstein-Barr virus viral capsid antigen. An immature ovarian teratoma was found and removal of the tumor resulted in a full recovery. The final diagnosis of anti-N-methyl-D-aspartate receptor encephalitis was made by the identification of anti-N-methyl-D-aspartate receptor antibodies in her cerebral spinal fluid. Pathology studies of the teratoma revealed N-methyl-D-aspartate receptor subunit 1 positive ectopic immature nervous tissue and Epstein-Barr virus latent infection. She was discharged with symptoms free, but titers of anti-thyroid peroxidase and anti-thyroglobulin antibodies remained elevated. One year after discharge, her serum remained positive for anti-thyroid peroxidase and anti-N-methyl-D-aspartate receptor antibodies, but negative for anti-thyroglobulin antibodies and IgM against Epstein-Barr virus viral capsid antigen.

Conclusions

Persistent high titers of anti-thyroid peroxidase antibodies from admission to discharge and until one year later in this patient may suggest a propensity to autoimmunity in anti- N-methyl-D-aspartate receptor encephalitis and support the idea that neuronal and thyroid autoimmunities represent a pathogenic spectrum. Enduring anti-N-methyl-D-aspartate receptor antibodies from admission to one year follow-up but seroreversion of Epstein-Barr virus viral capsid antigen IgM may raise the important issue of elucidating the triggers and boosters of anti- N-methyl-D-aspartate receptor encephalitis.

Highly efficient phosphorescent organic light-emitting diode with a nanometer-thick Ni silicide/polycrystalline p-Si composite anode

A phosphorescent organic light-emitting diode (PhOLED) with a nanometer-thick (approximately 10 nm) Ni silicide/ polycrystalline p-Si composite anode is reported. The structure of the PhOLED is Al mirror/ glass substrate / Si isolation layer / Ni silicide / polycrystalline p-Si/ V(2)O(5)/ NPB/ CBP: (ppy)(2)Ir(acac)/ Bphen/ Bphen: Cs(2)CO(3)/ Sm/ Au/ BCP. In the composite anode, the Ni-induced polycrystalline p-Si layer injects holes into the V(2)O(5)/ NPB, and the Ni silicide layer reduces the sheet resistance of the composite anode and thus the series resistance of the PhOLED. By adopting various measures for specially optimizing the thickness of the Ni layer, which induces Si crystallization and forms a Ni silicide layer of appropriate thickness, the highest external quantum efficiency and power conversion efficiency have been raised to 26% and 11%, respectively.

Inhibition of calcineurin-mediated endocytosis and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors prevents amyloid beta oligomer-induced synaptic disruption

Synaptic degeneration, including impairment of synaptic plasticity and loss of synapses, is an important feature of Alzheimer disease pathogenesis. Increasing evidence suggests that these degenerative synaptic changes are associated with an accumulation of soluble oligomeric assemblies of amyloid beta (Abeta) known as ADDLs. In primary hippocampal cultures ADDLs bind to a subpopulation of neurons. However the molecular basis of this cell type-selective interaction is not understood. Here, using siRNA screening technology, we identified alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunits and calcineurin as candidate genes potentially involved in ADDL-neuron interactions. Immunocolocalization experiments confirmed that ADDL binding occurs in dendritic spines that express surface AMPA receptors, particularly the calcium-impermeable type II AMPA receptor subunit (GluR2). Pharmacological removal of the surface AMPA receptors or inhibition of AMPA receptors with antagonists reduces ADDL binding. Furthermore, using co-immunoprecipitation and photoreactive amino acid cross-linking, we found that ADDLs interact preferentially with GluR2-containing complexes. We demonstrate that calcineurin mediates an endocytotic process that is responsible for the rapid internalization of bound ADDLs along with surface AMPA receptor subunits, which then both colocalize with cpg2, a molecule localized specifically at the postsynaptic endocytic zone of excitatory synapses that plays an important role in activity-dependent glutamate receptor endocytosis. Both AMPA receptor and calcineurin inhibitors prevent oligomer-induced surface AMPAR and spine loss. These results support a model of disease pathogenesis in which Abeta oligomers interact selectively with neurotransmission pathways at excitatory synapses, resulting in synaptic loss via facilitated endocytosis. Validation of this model in human disease would identify therapeutic targets for Alzheimer disease.

Insulin receptor dysfunction impairs cellular clearance of neurotoxic oligomeric a{beta}

Accumulation of amyloid beta (Abeta) oligomers in the brain is toxic to synapses and may play an important role in memory loss in Alzheimer disease. However, how these toxins are built up in the brain is not understood. In this study we investigate whether impairments of insulin and insulin-like growth factor-1 (IGF-1) receptors play a role in aggregation of Abeta. Using primary neuronal culture and immortal cell line models, we show that expression of normal insulin or IGF-1 receptors confers cells with abilities to reduce exogenously applied Abeta oligomers (also known as ADDLs) to monomers. In contrast, transfection of malfunctioning human insulin receptor mutants, identified originally from patient with insulin resistance syndrome, or inhibition of insulin and IGF-1 receptors via pharmacological reagents increases ADDL levels by exacerbating their aggregation. In healthy cells, activation of insulin and IGF-1 receptor reduces the extracellular ADDLs applied to cells via seemingly the insulin-degrading enzyme activity. Although insulin triggers ADDL internalization, IGF-1 appears to keep ADDLs on the cell surface. Nevertheless, both insulin and IGF-1 reduce ADDL binding, protect synapses from ADDL synaptotoxic effects, and prevent the ADDL-induced surface insulin receptor loss. Our results suggest that dysfunctions of brain insulin and IGF-1 receptors contribute to Abeta aggregation and subsequent synaptic loss.

[Studies on heredity rule of the first genealogy regarding fatal familial insomnia in Henan province]

OBJECTIVE

To investigate the epidemiological, genealogic characteristic, familial history of the families with fatal familial insomnia, its clinical and pathological features as well as the heredity rule of related genes.

METHODS

135 familial members of 7 eras were studied. Vein blood samples from patients as well as from some familial members were collected. PRNP gene was studied with PCR, its serial was determined and then authenticated with Nsp I . Brain tissue was obtained for neuropathological test and PrP(Sc) test with Western blot method.

RESULTS

Clinical symptoms of the 2 diagnosed cases were typical. 11 familial members died of similar neural disease. 32 samples of their familial members, codon at D178N of PRNP of 11 members was mutated, with mutation rate as 34.38% while D129N showed as methionine. Brain tissue of both probands denaturalized into spongiform and the nerve fiber was absent but PrP(Sc) protein was identified.

CONCLUSION

Genealogy was described in the family with fatal familial insomnia since the patients had typical clinical symptoms and pathological characteristics. It seemed necessary to confirm cases of fatal familial insomnia and their genealogy with epidemiological data and to investigate its gene characteristics as well as with neuropathological and Western blot tests.

First Report of Potato Scab Caused by Streptomyces turgidiscabies in China

Potato scab, caused by several plant pathogenic Streptomyces species, is known to occur in potato-planting areas worldwide. Symptoms of disease on potato tubers are shallow, raised, or pitted corky lesions (2). In 1998, Streptomyces turgidiscabies was reported as a new potato scab pathogen from Hokkaido, Japan (3). Potato scab has been observed in many potato-cultivation areas in China and incidence of the disease was approximately 6 to 10% in some fields in 2006 (in our survey). To investigate the casual agent of scab disease, isolations were made from scabby potato tubers collected from different areas using oatmeal agar. Identification of an isolate from Shaanxi Province was based on morphological and physiological characterization followed by 16S rRNA confirmation. Characteristics were gray, aerial hypha, rectiflexuous spore chains, a smooth spore surface, and spores that were 0.5 to 0.7 × 1.0 to 1.2 μm. The strain did not produce melanin on tyrosine-peptone-yeast extract agar media, did not produce diffusible pigments, used all the International Streptomyces Project (ISP) sugars (4) as single carbon sources, used l-hydroxyproline, l-tyrosine, and l-histidine as single nitrogen sources but not l-methionine, grew at pH 4.5, was susceptible to streptomycin (20 μg ml^-1), phenol (0.1%), and penicillin (10 IU ml^-1) but not to crystal violet (0.5 μg ml^-1), and produced H₂S. The identification was confirmed by comparison of its 16S rRNA sequence with the GenBank database using the BLAST program. The 16S rRNA sequence was amplified by PCR with primers S1: 5'-CATTCACGGAGAGTTTGATCC-3' and S2: 5'-AGAAAGGAGGTGATCCAGCC-3' and sequenced. BLASTn analysis of the sequence obtained showed the highest similarity (99.9%) with S. turgidiscabies type strain ATCC 700248 (GenBank Accession No. AB026221). The sequence was submitted to GenBank (Accession No. AM889495). Pathogenicity of the strain was tested in the greenhouse on potato tubers of cv. Favorita grown in pots (one plant per pot, three replicates). One hundred milliliters of inoculum (1 × 10⁵ CFU ml^-1) of the strain was mixed with sterile soil and vermiculite (1:1) in each pot. Potato plants were grown at 25°C and the soil was allowed to dry between waterings. The immature potato tubers were used to evaluate scab symptoms 10 weeks after planting. All tubers inoculated with the pathogen developed typical common scab symptoms consisting of erumpent, brown, corky lesions, which is different from the symptoms caused by S. reticuliscabiei (1). The noninoculated control tubers did not show scab symptoms. S. turgidiscabies was reisolated from lesions of diseased immature tubers. The pathogenicity test indicates that S. turgidiscabies caused scab disease on potato tubers. To our knowledge, this is the first report of S. turgidiscabies causing potato scab disease in China. References: (1) K. Bouchek-Mechiche et al. Int. J. Syst. Evol. Microbiol. 56:2771, 2006. (2) R. Loria et al. Plant Dis. 81:836, 1997. (3) K. Miyajima et al. Int. J. Syst. Bacteriol. 48:495, 1998. (4) E. B. Shirling and D. Gottlieb. Int. J. Syst. Bacteriol. 16:313, 1966.

Combination of passivated Si anode with phosphor doped organic to realize highly efficient Si-based electroluminescence

Silicon light source plays a key role in silicon optoelectronics, but its realization is an extremely challenging task. Although there are longterm intensive efforts to this topic, the power conversion efficiency (PCE) of the silicon-based electroluminescence is still no more than 1%. In this present report, a highly efficient silicon light source has been achieved. The device structure is p-Si (5 Omegacm)/ SiO2(approximately 2 nm)/ NPB / CBP: (ppy)(2)Ir(acac) / Bphen /Bphen: Cs2CO3 / Sm / Au. The SiO2 passivated Si is the anode having a suitably high hole-injection ability, and CBP: (ppy)(2)Ir(acac) is a highly efficient phosphor doped organic material. The device turn-on voltage is 3.2 V. The maximum luminance efficiency and maximum luminous power efficiency reach 69 cd/A and 62 lm/W, respectively, corresponding to a maximum PCE of 12% and an external quantum efficiency of 17%.

Amyloid beta oligomers induce impairment of neuronal insulin receptors

Recent studies have indicated an association between Alzheimer's disease (AD) and central nervous system (CNS) insulin resistance. However, the cellular mechanisms underlying the link between these two pathologies have not been elucidated. Here we show that signal transduction by neuronal insulin receptors (IR) is strikingly sensitive to disruption by soluble Abeta oligomers (also known as ADDLs). ADDLs are known to accumulate in AD brain and have recently been implicated as primary candidates for initiating deterioration of synapse function, composition, and structure. Using mature cultures of hippocampal neurons, a preferred model for studies of synaptic cell biology, we found that ADDLs caused a rapid and substantial loss of neuronal surface IRs specifically on dendrites bound by ADDLs. Removal of dendritic IRs was associated with increased receptor immunoreactivity in the cell body, indicating redistribution of the receptors. The neuronal response to insulin, measured by evoked IR tyrosine autophosphorylation, was greatly inhibited by ADDLs. Inhibition also was seen with added glutamate or potassium-induced depolarization. The effects on IR function were completely blocked by NMDA receptor antagonists, tetrodotoxin, and calcium chelator BAPTA-AM. Downstream from the IR, ADDLs induced a phosphorylation of Akt at serine473, a modification associated with neurodegenerative and insulin resistance diseases. These results identify novel factors that affect neuronal IR signaling and suggest that insulin resistance in AD brain is a response to ADDLs, which disrupt insulin signaling and may cause a brain-specific form of diabetes as part of an overall pathogenic impact on CNS synapses.

Treatment of scrapie pathogen 263K with tetracycline partially abolishes protease-resistant activity in vitro and reduces infectivity in vivo

OBJECTIVE

To study the possible effect of tetracycline on protease-resistant activity in vitro and infectivity in vivo of a scrapie strain 263K.

METHODS

Scrapie pathogens were incubated with tetracycline at different concentrations for various periods of time and protease-resistant PrP signals were evaluated with proteinase K-treatment and Western blots. The preparations treated with tetracycline were intracerebrally inoculated into golden hamsters and typical TSE manifestations were noted. PrPSc in brain tissues of the infected animals was detected by PrP specific Western blot assays.

RESULTS

Protease-resistant PrP was significantly reduced in or removed from the preparations treated with tetracycline in a dose-dependant manner. Compared with the control group after incubated for 53.75 +/- 0.50 days, the preparations treated with 5 mmol/L and 20 mmol/L tetracycline prolonged the incubation time of 61.5 +/- 1.73 and 59.5 +/- 0.58 days (P < 0.05).

CONCLUSION

Treatment of scrapie pathogen 263K with tetracycline reduces or removes its protease-resistant activity in vitro.

Expression of annexin A2 in GABAergic interneurons in the normal rat brain

Expression of the Ca(2+)-dependent phospholipids binding protein annexin A2 (ANX2) in the brain is thought to be largely associated with brain pathological conditions such as tumor, inflammation, and neurodegeneration. The recent findings that ANX2 heterotetramer is involved in learning and neuronal activities necessitates a systematic investigation of the physiological expression of ANX2 in the brain. With combination of in situ hybridization and immunohistochemistry, ANX2 mRNA and protein were specifically detected in a group of GABAergic interneurons throughout the brain. Although ANX2 was absent from the interior of pyramidal neurons, it was found on the membrane and seemly the extracellular space of those neurons, where they closely co-localized with glutamate decarboxylase terminals. In cultured developing neurons, ANX2 was present at high concentrations in the growth cones co-distributing with several growth-associated proteins such as growth associated protein 43 (GAP43), turned on after division/Ulip/CRMP (TUC-4), tubulin, and tissue-plasminogen activator. It then became predominantly distributed on the membrane and mostly in axonal branches as neurons grew and extended synaptic networks. ANX2 was also secreted from cultured neurons, in a membrane-bound form that was Ca(2+)-dependent, which was significantly increased by neuronal depolarization. These results may have implications in the function and regulatory mechanism of ANX2 in the normal brain.

Wernicke's encephalopathy in nonalcoholic patients: clinical and pathologic features of three cases and literature reviewed

Three cases of Wernicke's encephalopathy in nonalcoholic patients diagnosed by postmortem examination were reported to improve the recognition of this disease. All three cases were male, ages ranged from 33 to 73 years old. All the cases had a clinical history of malnutrition but no history of chronic alcoholism. Routine autopsy and neuropathologic investigations examining the histological changes of the brain were performed. Pathological findings included recent petechial and local hemorrhages in the mamillary bodies, periventricular regions around the third and fourth ventricles and aqueduct. Under light microscopy the proliferation and dilatation of the capillaries was particularly prominent in the mamillary bodies and pericapillary hemorrhages were present in the periventricular regions. Neuronal losses were found only in the medial nucleus of the thalamus and inferior olive, myelin staining demonstrated demyelination and gliosis in those areas. The diagnosis of Wernicke's encephalopathy was made. In combination with the reviewed literature, our cases suggest that Wernicke's encephalopathy can occur not only in patients with alcohol abuse, but also in those who have suffered thiamine deficiency due to metabolic and nutritional disorders.

Insulin receptor signaling in long-term memory consolidation following spatial learning

Evidence has shown that the insulin and insulin receptor (IR) play a role in cognitive function. However, the detailed mechanisms underlying insulin's action on learning and memory are not yet understood. Here we investigated changes in long-term memory-associated expression of the IR and downstream molecules in the rat hippocampus. After long-term memory consolidation following a water maze learning experience, gene expression of IR showed an up-regulation in the CA1, but a down-regulation in the CA3 region. These were correlated with a significant reduction in hippocampal IR protein levels. Learning-specific increases in levels of downstream molecules such as IRS-1 and Akt were detected in the synaptic membrane accompanied by decreases in Akt phosphorylation. Translocation of Shc protein to the synaptic membrane and activation of Erk1/2 were also observed after long-term memory formation. Despite the clear memory-correlated alterations in IR signaling pathways, insulin deficits in experimental diabetes mellitus (DM) rats induced by intraperitoneal injections of streptozotocin resulted in only minor memory impairments. This may be due to higher glucose levels in the DM brain, and to compensatory mechanisms from other signaling pathways such as the insulin-like growth factor-1 receptor (IGF-1R) system. Our results suggest that insulin/IR signaling plays a modulatory role in learning and memory processing, which may be compensated for by alternative pathways in the brain when an insulin deficit occurs.

Increased glucose tolerance and reduced adiposity in the absence of fasting hypoglycemia in mice with liver-specific Gs alpha deficiency

The G protein G(s)alpha is essential for hormone-stimulated cAMP generation and is an important metabolic regulator. We investigated the role of liver G(s)-signaling pathways by developing mice with liver-specific G(s)alpha deficiency (LGsKO mice). LGsKO mice had increased liver weight and glycogen content and reduced adiposity, whereas survival, body weight, food intake, and metabolic rates at ambient temperature were unaffected. LGsKO mice had increased glucose tolerance with both increased glucose-stimulated insulin secretion and increased insulin sensitivity in liver and muscle. Fed LGsKO mice were hypoglycemic and hypoinsulinemic, with low expression of hepatic gluconeogenic enzymes and PPARgamma coactivator-1. However, LGsKO mice maintained normal fasting glucose and insulin levels, probably due to prolonged breakdown of glycogen stores and possibly increased extrahepatic gluconeogenesis. Lipid metabolism was unaffected in fed LGsKO mice, but fasted LGsKO mice had increased lipogenic and reduced lipid oxidation gene expression in liver and increased serum triglyceride and FFA levels. LGsKO mice had very high serum glucagon and glucagon-like peptide-1 levels and pancreatic alpha cell hyperplasia, probably secondary to hepatic glucagon resistance and/or chronic hypoglycemia. Our results define novel roles for hepatic G(s)-signaling pathways in glucose and lipid regulation, which may prove useful in designing new therapeutic targets for diabetes and obesity.

Insulin and the insulin receptor in experimental models of learning and memory

Insulin is best known for its action on peripheral insulin target tissues such as the adipocyte, muscle and liver to regulate glucose homeostasis. In the central nervous system (CNS), insulin and the insulin receptor are found in specific brain regions where they show evidence of participation in a variety of region-specific functions through mechanisms that are different from its direct glucose regulation in the periphery. While the insulin/insulin receptor associated with the hypothalamus plays important roles in regulation of the body energy homeostasis, the hippocampus- and cerebral cortex-distributed insulin/insulin receptor has been shown to be involved in brain cognitive functions. Emerging evidence has suggested that insulin signaling plays a role in synaptic plasticity by modulating activities of excitatory and inhibitory receptors such as glutamate and GABA receptors, and by triggering signal transduction cascades leading to alteration of gene expression that is required for long-term memory consolidation. Furthermore, deterioration of insulin receptor signaling appears to be associated with aging-related brain degeneration such as the Alzheimer's dementia and cognitive impairment in aged subjects suffering type 2 diabetes mellitus.

Insulin and the insulin receptor in experimental models of learning and memory

Insulin is best known for its action on peripheral insulin target tissues such as the adipocyte, muscle and liver to regulate glucose homeostasis. In the central nervous system (CNS), insulin and the insulin receptor are found in specific brain regions where they show evidence of participation in a variety of region-specific functions through mechanisms that are different from its direct glucose regulation in the periphery. While the insulin/insulin receptor associated with the hypothalamus plays important roles in regulation of the body energy homeostasis, the hippocampus- and cerebral cortex-distributed insulin/insulin receptor has been shown to be involved in brain cognitive functions. Emerging evidence has suggested that insulin signaling plays a role in synaptic plasticity by modulating activities of excitatory and inhibitory receptors such as glutamate and GABA receptors, and by triggering signal transduction cascades leading to alteration of gene expression that is required for long-term memory consolidation. Furthermore, deterioration of insulin receptor signaling appears to be associated with aging-related brain degeneration such as the Alzheimer's dementia and cognitive impairment in aged subjects suffering type 2 diabetes mellitus.

Specific localization of the annexin II heterotetramer in brain lipid raft fractions and its changes in spatial learning

Annexin-II (AII) is a Ca(2+)-dependent phospholipid-binding protein that is present in both intracellular and extracellular compartments. In the present study AII immunoreactivity was found in a subpopulation of neurons in specific brain regions, including the cerebral cortex and the surface of hippocampal pyramidal neurons from adult rats. AII from synaptic membranes was detected by immunoblotting as multiple species containing the monomer (AII36) and heterotetramer (AIIt). AIIt was resistant to beta-mercaptoethanol and dithiothreitol in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, but was completely reduced to monomers (36 kDa) by two-dimensional electrophoresis. AIIt resided exclusively in the detergent-resistant lipid rafts concentrated in neuronal dendrites, and its recruitment to those structures was enhanced by antibody cross-link. AII abundantly distributed on the outer leaflet of neuronal membranes and between spaces of neurons appeared to be neuronal adhesive. The formation of AIIt required synthesis of sphingolipids and cholesterol, and its stability depended on Ca2+. Increases in neuronal activities such as depolarization and learning were shown to promote formation of AIIt. Our results suggest that, via a dynamic association with dendritic lipid rafts, AII may play a role in synaptic signal transduction and remodeling. This probably involves focal adhesion and interactions with actin that are associated with brain development and memory consolidation.

Impairment of phosphatase 2A contributes to the prolonged MAP kinase phosphorylation in Alzheimer's disease fibroblasts

The serine/threonine phosphatase 2A (PP2A) has been implicated in the pathogenesis of Alzheimer's disease (AD) due to its important role in regulating dephosphorylation of the microtubule-associated protein tau and mitogen-activated protein (MAP) kinase. In the present study, we show that PP2A was responsible for dephosphorylation of the extracellular signal-regulated kinase 1/2 (Erk1/2) following its activation by BK stimulation. Abnormal gene and protein expressions of PP2A, as well as its activity, were found to contribute to the abnormally prolonged Erk1/2 phosphorylation in the AD fibroblasts. Inhibition of PP2A with okadiac acid produced enhanced and more lasting Erk1/2 phosphorylation after BK stimulation, whereas FK506, an inhibitor of PP2B and FK-binding protein, inhibited the BK-stimulated Erk1/2 phosphorylation. Furthermore, while the phosphorylated Erk1/2 was concentrated in the nucleus of AC cells, it was mainly distributed in the extranuclear compartments of AD cells. These results suggest that the delayed dephosphorylation of Erk1/2 in AD cells following its BK-stimulated activation may be due to deficits of PP2A activity and impaired nuclear translocation of phosphorylated Erk1/2.

Gene expression of alpha-endosulfine in the rat brain: correlative changes with aging, learning and stress

Endosulfine (EDSF) belongs to a highly conserved cAMP-regulated phosphoprotein (ARPP) family and was first isolated from ovine brain as a possible endogenous ligand for sulfonylurea receptors. To explore its involvement in brain functions, we investigated regional distribution of alpha-EDSF gene expression in the rat brain, and its regulation under physiological and pathological conditions. The majority of alpha-EDSF gene was expressed in the pyramidal neurons, which represent the principal excitatory neurons in various brain regions. Down-regulation of alpha-EDSF mRNA was detected in the rat hippocampus during long-term memory consolidation following a spatial learning experience, whereas swimming-related stress caused persistent up-regulation of alpha-EDSF gene expression in several brain regions. These changes, however, were absent from brains of diabetic rats that were subjected to the same behavioral treatments. Intracerebroventricular injection of streptozocin with a toxic dose induced severe learning deficits and brain structure alteration accompanied by a massive increase of alpha-EDSF mRNA in the somatosensory cortex. These results suggest that alpha-EDSF gene expression is differentially regulated by distinct brain processes involving excitatory neuronal activities.

c-Src protein tyrosine kinase activity is required for muscarinic receptor-mediated DNA synthesis and neurogenesis via ERK1/2 and c-AMP-responsive element-binding protein signaling in neural precursor cells

The G protein-coupled muscarinic acetylcholine receptor (mAChR) isoforms have been identified in neural stem/progenitor (or precursor) cells. In previous studies, activation of these receptors induced elevations in intracellular Ca(2+) signals and mitogen-activated protein (MAP) kinase activity that led to enhanced DNA synthesis along with neurogenesis in neural precursor cells. Here we report that the nonreceptor protein tyrosine kinase c-src activity is required for the muscarinic receptor-activated MAP kinase and cAMP-responsive element-binding protein (CREB). Stimulation of neural precursor cells dissociated from embryonic day 13 rat cortical neuroepithelium with the muscarinic receptor agonist carbachol (CCh) induced phosphorylations of c-src that were detected by antibodies raised against phospho-Tyr416 (Ptyr416), phospho-Tyr527 (Ptyr527), and phospho-Tyr215 (Ptyr215) of the kinase. Although an increase in Ptyr416 suggested direct activation of c-src, Ptyr215 may serve as an alternative mechanism underlying activation of c-src without dephosphorylation of Ptyr-527. Both extracellular signal-regulated kinase (Erk1/2) and CREB were significantly activated after CCh treatment indicated by increases in phosphorylation of these two proteins. The c-Src inhibitor PP1 abolished the CCh-induced activation of Erk1/2 and CREB in a dose-dependent manner. Moreover, CCh stimulated expression of the neuronal specific marker MAP2, which was inhibited by PP1. Cell proliferation assays and immunocytochemistry revealed that PP1 inhibited the CCh-induced DNA synthesis and MAP2(+) production. These results suggest that c-src activity is essential for the muscarinic receptor-mediated proliferation and neurogenesis in neural precursor cells via Erk1/2 and CREB signaling pathways.

Secretion of Annexin II via activation of insulin receptor and insulin-like growth factor receptor

Annexin II is secreted into the extracellular environment, where, via interactions with specific proteases and extracellular matrix proteins, it participates in plasminogen activation, cell adhesion, and tumor metastasis and invasion. However, mechanisms regulating annexin II transport across the cellular membrane are unknown. In this study, we used coimmunoprecipitation to show that Annexin-II was bound to insulin and insulin-like growth factor-1 (IGF-1) receptors in PC12 cells and NIH-3T3 cells overexpressing insulin (NIH-3T3(IR)) or IGF-1 receptor (NIH-3T3(IGF-1R)). Stimulation of insulin and IGF-1 receptors by insulin caused a temporary dissociation of annexin II from these receptors, which was accompanied by an increased amount of extracellular annexin II detected in the media of PC12, NIH-3T3(IR), and NIH-3T3(IGF-1R) cells but not in that of untransfected NIH-3T3 cells. Activation of a different growth factor receptor, the platelet-derived growth factor receptor, did not produce such results. Tyrphostin AG1024, a tyrosine kinase inhibitor of insulin and IGF-1 receptor, was shown to inhibit annexin II secretion along with reduced receptor phosphorylation. Inhibitors of a few downstream signaling enzymes including phosphatidylinositol 3-kinase, pp60c-Src, and protein kinase C had no effect on insulin-induced annexin II secretion, suggesting a possible direct link between receptor activation and annexin II secretion. Immunocytochemistry revealed that insulin also induced transport of the membrane-bound form of annexin II to the outside layer of the cell membrane and appeared to promote cell aggregation. These results suggest that the insulin receptor and its signaling pathways may participate in molecular mechanisms mediating annexin II secretion.

MAP kinase signaling cascade dysfunction specific to Alzheimer's disease in fibroblasts

Mitogen-activated protein kinases (such as Erk1/2) regulate phosphorylation of the microtubule-associated protein tau and processing of the amyloid protein beta, both events critical to the pathophysiology of Alzheimer's disease (AD). Here we report that enhanced and prolonged Erk1/2 phosphorylation in response to bradykinin (BK) was detected in fibroblasts of both familial and sporadic AD, but not age-matched controls (AC). The AD-associated abnormality in Erk1/2 phosphorylation was not seen in fibroblasts from Huntington's disease patients with dementia. The elevation of Erk1/2 phosphorylation occurred immediately after BK stimulation and required an IP3-sensitive Ca(2+) release as well as activation of PKC and c-src as upstream events. Treatment of cells with the PI-3 kinase blocker LY924002 partially inhibited the BK-stimulated Erk1/2 phosphorylation in AC, but had no effect in AD cells, suggesting that the BK-induced Erk1/2 phosphorylation in AD cells is independent of PI-3 kinase. Activation of the cAMP-responsive element binding protein (CREB) monitored as an increase in phosphorylation at Ser-133 was also observed after BK stimulation. Unlike the AD-specific differences for Erk1/2, however, the BK-stimulated CREB phosphorylation was not different between AC and AD cells. Abnormal Erk1/2 activities may alter downstream cellular processes such as gene transcription, amyloid precursor protein processing, and tau protein phosphorylation, which contribute to the pathogenesis of AD. Moreover, detection of AD-specific differences in MAP kinase in peripheral tissues may provide an efficient means for early diagnosis of AD as well as help us to identify therapeutic targets for drug discovery.

L-dopa upregulates the expression and activities of methionine adenosyl transferase and catechol-O-methyltransferase

High nonphysiological doses of l-dopa are administered to Parkinson's disease (PD) patients, to replenish the depleted dopamine (DA). A large portion of the administered L-dopa and the newly formed DA undergoes methylation by reacting with S-adenosyl-L-methionine (SAM). In the process SAM, as well as L-dopa and DA, is utilized and great demands are placed on the transmethylation system. In this study we investigated whether L-dopa increases the transmethylation process by inducing methionine adenosyl transferase (MAT), the enzyme that produces SAM, and catechol-O-methyl transferase (COMT), the enzyme that transfers the methyl group from SAM to L-dopa and DA. Swiss Webster mice were injected with L-dopa, four times/day, for 1 to 16 days. Brain DA, 3-O-methyldopa (3-OMD), SAM, S-adenosylhomocysteine (SAH), MAT, and COMT were measured following a 24-h withdrawal period. An increase of 264% of brain DA occurred at days 2 and 3 after which it tapered to about 164% of control. The brain level of 3-OMD increased to 870% of the control. SAM was increased by 44% after the sixth day and SAH level was about double after the second day. After day 3, MAT activity was increased by about 35%. Western blot analysis showed that MAT is more clearly characterized in 10% mercaptoethanol reducing buffer in which 31.5-, 38- (beta), and 48-kDa (alpha1/alpha2) subunits were distinctly revealed. The induction of the 38-kDa and, more prominently, the 48-kDa subunits of MAT and the potential transactivator proteins of MAT, c-Jun/AP-1, was evident by day 6. The 31.5-kDa subunit was downregulated. COMT was detected as 24.7-, 30-, and 47.5-kDa bands in the brain, consistent with the membrane-bound COMT I (MB-COMT) and the dimeric COMT II. The 24.7- and the 30-kDa MB-COMT bands were induced in the brain by day 6 and peaked on day 9. The highlight of the study is the fact that L-dopa induces the enzymes MAT and COMT. In addition, the downturn in brain DA after the sixth day coincides with the increase in SAM and the 48-kDa MAT protein. Thus, during PD treatment with L-dopa the induction of MAT and COMT is likely to occur and in turn increase the methylation and reduction of L-dopa and DA that may help cause the tolerance or the wearing-off effect developed to L-dopa.

Role of insulin and insulin receptor in learning and memory

As one of the most extensively studied protein hormones, insulin and its receptor have been known to play key roles in a variety of important biological functions. Until recent years, the functions of insulin and insulin receptor (IR) in the central nervous system (CNS) have largely remained unclear. IR is abundantly expressed in several specific brain regions that govern fundamental behaviors such as food intake, reproduction and high cognition. The IR from the periphery and CNS exhibit differences in both structure and function. In addition to that from the peripheral system, locally synthesized insulin in the brain has also been identified. Accumulated evidence has demonstrated that insulin/IR plays important roles in associative learning, as suggested by results from both interventive and correlative studies. Interruption of insulin production and IR activity causes deficits in learning and memory formation. Abnormal insulin/IR levels and activities are seen in Alzheimer's dementia, whereas administration of insulin significantly improves the cognitive performance of these patients. The synaptic bases for the action of insulin/IR include modifying neurotransmitter release processes at various types of presynaptic terminals and modulating the activities of both excitatory and inhibitory postsynaptic receptors such as NMDA and GABA receptors, respectively. At the molecular level, insulin/IR participates in regulation of learning and memory via activation of specific signaling pathways, one of which is shown to be associated with the formation of long-term memory and is composed of intracellular molecules including the shc, Grb-r/SOS, Ras/Raf, and MEK/MAP kinases. Cross-talk with another IR pathway involving IRS1, PI3 kinase, and protein kinase C, as well as with the non-receptor tyrosine kinase pp60c-src, may also be associated with memory processing.

Theta rhythm of hippocampal CA1 neuron activity: gating by GABAergic synaptic depolarization

Information processing and memory consolidation during exploratory behavior require synchronized activity known as hippocampal theta (theta) rhythm. While it is well established that the theta activity depends on cholinergic inputs from the medial septum/vertical limb of the diagonal band nucleus (MS/DBv) and theta discharges of GABAergic interneurons, and can be induced with cholinergic receptor agonists, it is not clear how the increased excitation of pyramidal cells could occur with increased discharges of GABAergic interneurons during theta waves. Here, we show that the characteristic theta activity in adult rat hippocampal CA1 pyramidal cells is associated with GABAergic postsynaptic depolarization and a shift of the reversal potential from Cl(-) toward HCO(3)(-) (whose ionic gradient is regulated by carbonic anhydrase). The theta activity was abolished by GABA(A) receptor antagonists and carbonic anhydrase inhibitors, but largely unaffected by blocking glutamate receptors. Carbonic anhydrase inhibition also impaired spatial learning in a water maze without affecting other sensory/locomotor behaviors. Thus HCO(3)(-)-mediated signaling, as regulated by carbonic anhydrase, through reversed polarity of GABAergic postsynaptic responses is implicated in both theta and memory consolidation in rat spatial maze learning. We suggest that this mechanism may be important for the phase forward shift of the place cell discharges for each theta cycle during the animal's traversal of the place field for that cell.

Calexcitin interaction with neuronal ryanodine receptors

Calexcitin (CE), a Ca2+- and GTP-binding protein, which is phosphorylated during memory consolidation, is shown here to co-purify with ryanodine receptors (RyRs) and bind to RyRs in a calcium-dependent manner. Nanomolar concentrations of CE released up to 46% of the 45Ca label from microsomes preloaded with 45CaCl2. This release was Ca2+-dependent and was blocked by antibodies against the RyR or CE, by the RyR inhibitor dantrolene, and by a seven-amino-acid peptide fragment corresponding to positions 4689-4697 of the RyR, but not by heparin, an Ins(1,4,5)P3-receptor antagonist. Anti-CE antibodies, in the absence of added CE, also blocked Ca2+ release elicited by ryanodine, suggesting that the CE and ryanodine binding sites were in relative proximity. Calcium imaging with bis-fura-2 after loading CE into hippocampal CA1 pyramidal cells in hippocampal slices revealed slow, local calcium transients independent of membrane depolarization. Calexcitin also released Ca2+ from liposomes into which purified RyR had been incorporated, indicating that CE binding can be a proximate cause of Ca2+ release. These results indicated that CE bound to RyRs and suggest that CE may be an endogenous modulator of the neuronal RyR.

Peptidyl-prolyl-cis/trans-isomerase activity may be necessary for memory formation

At present, evidence for a plethora of physiological roles for the different classes of peptidyl-prolyl-cis/trans-isomerases (PPIases, EC 5.2.1.8) is emerging. Cyclosporin A (CyA) has been previously reported to disrupt memory formation in a temporally specific manner, when administered intracranially to day-old chicks trained on a single-trial, passive-avoidance task [Bennett, P.C., Zhao, W., Lawen, A. and Ng, K.T. (1996) Brain Res. 730, 107-1171. CyA is known to inhibit both the PPIase activity of cyclophilin and, indirectly, the protein phosphatase activity of calcineurin. Therefore to begin to distinguish between these two functions we studied the effects on memory formation of three non-immunosuppressive CyA analogues, in order to study the involvement of cyclophilins. These drugs retain the capacity to bind to and inhibit the PPIase activity of cyclophilin, but do not bind in the complex with cyclophilin to calcineurin and, therefore, do not inhibit its phosphatase activity. All three drugs exert effects on memory formation comparable to those induced by CyA, significantly inhibiting memory formation when injected intracranially (50 fmol per hemisphere) immediately following training. Brain extracts from chicks treated with [MeVal4]CyA show a strong inhibition of cyclophilin activity. These data show a requirement for the PPIase activity of a cyclophilin for successful memory formation and constitute the first set of data establishing a physiological role for a cyclophilin.

Cell cycle-associated accumulation of tissue inhibitor of metalloproteinases-1 (TIMP-1) in the nuclei of human gingival fibroblasts

We first confirmed an earlier immunohistochemical study showing that immunoreactive TIMP-1-like protein accumulated in the nuclei of human gingival fibroblasts (Gin-1 cells), reaching a maximum in the S phase of the cell cycle (Li, H., Nishio, K., Yamashita, K., Hayakawa, T. and Hoshino, T. (1995). Nagoya J. Med. Sci. 58, 133–142). Then we isolated this protein from a nuclear extract of Gin-1 cells and demonstrated it to be identical to human recombinant TIMP-1 by western blotting, by a sandwich enzyme immunoassay for TIMP-1 and by an assay for matrix metalloproteinase inhibition. The amount of TIMP-1 in the cytosolic fraction of quiescent Gin-1 cells after stimulation by fetal calf serum increased continuously for 48 hours, whereas that in the nuclear extract showed a maximum at 24 hours (S phase) and significantly decreased thereafter. Gin-1 cells expressed mRNAs for both TIMP-2 and TIMP-3 together with mRNA for TIMP-1. However, neither TIMP-2 nor TIMP-3 proteins seemed to accumulate in the nuclei of Gin-1 cells. These facts strongly suggest that TIMP-1 accumulates specifically in the nuclei of Gin-1 cells in a cell cycle-dependent manner.

Chicks injected with antisera to either S-100 alpha or S-100 beta protein develop amnesia for a passive avoidance task

The cellular expression of S-100 beta protein is upregulated in Alzheimer's disease and in Down's syndrome, and this protein has been implicated in memory-related processes in laboratory animals. However, the possibility that the alpha subunit of S-100 is also involved in memory has not yet been examined. In the present study, day-old black Australorp white Leghorn cockerel chicks (Gallus domesticus) received injections of monoclonal antisera to S-100 alpha (1:50) or S-100 beta (1:500) into each hemisphere immediately after training on a one-trial passive avoidance task. The chicks displayed significantly lower retention levels than control birds that had been injected with antisera to carbonic anhydrase, or with saline (p < .01). S-100 alpha antisera had an amnestic effect when injected between 0 and 20 min after training, with memory deficits occurring from 30 min post-learning, at the point of transition between the A and the B phases of the Gibbs-Ng intermediate memory stage. By contrast, the S-100 beta antisera needed to be injected either 5 min before or immediately after training and produced amnesia 10 min earlier, at the start of the A phase of the intermediate memory stage. We conclude that the two subunits of the S-100 protein are required at different points in the sequence of events leading to the consolidation of passive avoidance memory.

Inhibition of intermediate-term memory following passive avoidance training in neonate chicks by a presynaptic cholinergic blocker

The effects of a specific presynaptic cholinergic antagonist, toosendanin, on memory formation following a passive avoidance training experience in day-old chicks was investigated. Bilateral injection of toosendanin into the neostriatal/hyperstriatal region of the chick forebrain produced memory impairment in a dose-dependent manner. Retention deficits were apparent from 20 min following training in chicks treated with toosendanin, regardless of the injection time relative to training. Chicks that received injections of the drug at corresponding times prior to retention tests showed normal retention levels, suggesting that toosendanin has no effect on performance and memory retrieval. These results indicate an involvement of cholinergic transmission during an early stage of memory formation.

Complex roles of glutamate in the Gibbs-Ng model of one-trial aversive learning in the new-born chick

Glutamate is the most widespread excitatory transmitter in the CNS and is probably involved in LTP, a neural phenomenon which may be associated with learning and memory formation. Intracerebral injection of large amounts of glutamate between 5 min and 2.5 min after passive avoidance learning in young chicks inhibits short-term memory, which occurs between 0 and 10 min post-learning in a three-stage model of memory formation first established by Gibbs and Ng(25) [Physiol. Behav. 23:369-375; 1979]. This effect may be attributed to non-specific excitation. Blockade of glutamate uptake by L-aspartic and beta-hydroxamate also abolishes this stage of memory, provided the drug is administered within 2.5 min of learning. Interference with either production of percursors for transmitter glutamate in astrocytes or with glutamate receptors is also detrimental to memory formation, but the effects appear much later. After its release from glutamatergic neurons, glutamate is, to a large extent, accumulated into astrocytes where it is converted to glutamine, which can be returned to glutamatergic neurons and reutilized for synthesis of transmitter glutamate, and partly oxidized as a metabolic substrate. The latter process leads to a net loss of transmitter glutamate which can be compensated for by de novo synthesis of a glutamate precursor alpha-ketoglutarate (alpha KG) in astrocytes, a process which is inhibited by the astrocyte-specific toxin fluoroacetate (R. A. Swanson, personal communication). Intracerebral injection of this toxin abolishes memory during an intermediate stage of memory processing occurring between 20 and 30 min post-training (50) [Cog. Brain Res, 2:93-102; 1994]. Injection of methionine sulfoximine (MSO), a specific inhibitor of glutamine synthetase, which interferes with the re-supply of transmitter glutamate to neurons by inhibition of glutamine synthesis in astrocytes, has a similar effect. This effect of MSO is prevented by intracerebral injection of glutamate, glutamine, or a combination and alpha KG and alanine. MSO must be administered before learning, but does not interfere with acquisition since short-term memory remains intact. Administration of either the NMDA antagonist AP5, the AMPA antagonist DNQX, or the metabotropic receptor antagonist MCPF, also induces amnesia. Memory loss in each case does not occur until after 70 min post-training, during a protein synthesis-dependent long-term memory stage which begins at 60 min following learning. However, to be effective, AP5 must be administered within 60 s following learning, MCPG before 15 min post-learning, and DNQX between 15 and 25 min after learning. Together, these findings suggest that learning results in an immediate release of glutamate, followed by a secondary release of this transmitter at later stages of processing of the memory trace, and that one or both of these increases in extracellular glutamate concentration are essential for the consolidation of long-term memory. Since both fluoroacetate and MSO act exclusively on glial cells, the findings also show that neuronal-glial interactions are necessary during the establishment of memory.

The involvement of Ca2+/calmodulin-dependent protein kinase in memory formation in day-old chicks

Day-old chicks trained on a single trial passive avoidance learning task showed a significant increase, relative to untrained controls, in activity of the Ca2+/calmodulin-dependent protein kinase (CaMK) in the particulate fraction from tissues from the intermediate medial hyperstriatum ventrale region of the forebrain. The increased kinase activity was observed within 10 min following training and persisted for at least 70 min posttraining. Amnesia for the task was induced by micromolar concentrations of the specific CAMK II antagonist, KN-62, administered into the neostriatal/hyperstriatal region of the forebrain. The effect of KN-62 was lateralized. In the right hemisphere, KN-62 induced amnesia only when injected within 2. 5 min following training, with memory loss evident by 5 min posttraining. In contrast, in the left hemisphere amnesia was induced by KN-62 administered as late as 5 min posttraining, with onset of amnesia occurring after 10 min posttraining. The findings were interpreted within the context of a three-stage model of memory formation.

Inhibitors of cAMP-dependent protein kinase impair long-term memory formation in day-old chicks

There is substantial evidence that protein kinases, through the phosphorylation of substrate proteins, play a significant role in information processing in the brain, including processes underlying memory formation. Inhibition of the activity of the cyclic-adenosine monophosphate-dependent protein kinase A by the highly specific inhibitor, halofantrine, resulted in impairment of memory formation in day-old chicks trained on a single-trial passive avoidance task. A dose of 9.6 ng/chick halofantrine induced amnesia at the beginning of a protein synthesis-dependent long-term memory stage, the last of three stages of memory postulated to underly memory formation in the chick following passive avoidance learning. The concentration of halofantrine required for 50% inhibition of chick brain protein kinase A was found to be similar to that observed for bovine heart and rat liver. The amnestic effect of halofantrine is tentatively attributed to interference with de novo protein synthesis necessary for long-term memory consolidation. Neither anthraquinone nor the anthraquinone derivative anthraflavic acid, which have little effect on protein kinase A activity, affected memory retention. On the other hand, two other anthraquinone derivatives, chrysophanic acid and purpurin, which inhibit PKA activity, at doses of 0.25 and 0.5 ng/chick also yielded retention deficits. In these cases, however, retention losses occurred earlier than observed with halofantrine, at about 30 min post-training. The earlier effects of these inhibitors may be due to the additional inhibitory action of these compounds on protein kinase C activity, which has been demonstrated in previous studies to be implicated, possibly through phosphorylation of the GAP43 phosphoprotein, in memory processing in the stage of memory immediately preceding the protein synthesis-dependent long-term stage.

2-deoxygalactose interferes with an intermediate processing stage of memory

The effect of 2-deoxygalactose (2-D-gal), an inhibitor of glycoprotein synthesis, on memory formation was investigated with the day-old chick trained on a single-trial passive discrimination task. 2-D-gal (10 mumol/chick) was shown to inhibit memory formation at a time before the emergence of an antibiotic-sensitive long-term memory stage. The amnestic effect of 2-D-gal was successfully prevented by galactose, and more significantly by noradrenaline. In contrast, anisomycin-induced amnesia was resistant to challenge by either galactose or noradrenaline. The results are consistent with the view that some glycoprotein involvement in memory formation occurs prior to the formation of protein synthesis-dependent long-term memory, and this role of glycoproteins may be associated with the triggering of long-term memory formation by noradrenaline.

Effect of PKC inhibitors and activators on memory

Changes in the activity of the enzyme protein kinase C (PKC) have been implicated in learning and memory consolidation, and in the induction of long-term potentiation. The precise role of PKC in memory processing is still unknown. Using 1-day-old chicks trained on a single-trial passive avoidance task, we demonstrate that inhibition of PKC activity by melittin induced retention loss, in a dose-dependent manner, in the second stage of a three-stage sequence of memory processing. The effect was lateralized to the left hemisphere of the chick forebrain. This effect of melittin was prevented by high concentrations (16-320 microM) of the PKC activator, phorbol 12-myristate 13-acetate (PMA). Furthermore, concentrations of PMA in the range 1.6 to 40 microM were shown to induce long-term memory consolidation following a weakly reinforced version of the learning task, which normally does not lead to formation of long-term memory. That these actions of PMA are attributable to PKC activation is supported by the further finding that the inactive phorbol ester 4 alpha-PDD had no effect either on melittin-induced amnesia or on memory consolidation following weakly reinforced learning. Paradoxically, concentrations of 16 microM or higher of PMA inhibited memory consolidation for the normal strongly reinforced learning trial, an effect again not observed with 40 alpha-PDD. The results are consistent with the view that PKC activity may be implicated in a pre-long-term stage of memory processing.

Purified antichick Thy-1 IgG abolishes intermediate and long-term memory

One- to 2-day-old chicks administered purified antichick Thy-1 IgG showed substantial amnesia for a single-trial passive discriminated avoidance task. Amnesia was clearly evident at 30 min after learning, during the intermediate stage of a three-stage model of memory processing, and persisted for at least 3 h. A similar effect was also observed with Fab and F(ab')2 fragments. Fc fragments, the non-IgG fraction of ascites, and saline yielded normal retention levels at all times. These results contrast with our earlier reports that both polyclonal and monoclonal antibodies to chick Thy-1 inhibited long-term memory formation only. The present findings are interpreted as possibly representing a dual effect of the purified IgG.

[Kinetic observation on BRC immune function of patients with epidemic hemorrhagic fever]

The RBC immune function of 88 patients with epidemic haemorrhagic fever (EHF) was examined kinetically with complement-labeled yeast method established by Guo Feng. The results showed that the percentage of RBC c3b receptor rossette, activity of RCIA-enhancing factor and c3 in sera of patients during the 3 different phases of EHF were markedly lower than those of the normal controls, while the percentage of RBC IC rossete, activity of RCIA-inhibiting factor and CIC in sera of the patients were manifestly higher (P less than 0.01). The change of all the indices observed above was most apparent in oliguric phase. This suggested that RBC immune function is lowered in the process of EHF.