Characterization of the domains of the erythropoietin receptor necessary for induction of cell growth and differentiation

To define the cytoplasmic region(s) of the erythropoietin receptor (EpoR) necessary for promotion of growth and induction of differentiation, mutated EpoR cDNAs containing truncations and conversions of tyrosine residues to phenylalanines were generated. Constructs were introduced into IL-3 dependent Ba/F3 cells by electroporation, and individual transfectants were propagated in methylcellulose-containing medium in the presence of erythropoietin (Epo). Truncated receptor at amino acid 350 was partially deficient in promoting cellular growth and the receptor lacking the box 2 region was not capable of inducing cellular growth. When a large number of cells were screened in Epo-containing liquid medium, clones arose in which Epo-dependent growth was due to activation of the endogenous EpoR gene. Analysis of the degree of Epo-dependent differentiation of the transfectants, based on the steady-state levels of beta major-globin mRNA, showed that the carboxyl terminal 133 amino acids and tyrosyl residues located at positions 429/431 and 460/464 were not necessary for the induction of differentiation. Examination of clones from diverse origins demonstrated that an inverse relationship existed between the rate of Epo-induced cellular replication and the degree of Epo-induced differentiation.

Activation of tau protein kinase I/glycogen synthase kinase-3beta by amyloid beta peptide (25-35) enhances phosphorylation of tau in hippocampal neurons

According to the amyloid hypothesis for the pathogenesis of Alzheimer's disease (AD), amyloid beta peptide (Abeta) directly affects neurons, leading to neurodegeneration and tau phosphorylation, followed by the production of paired helical filaments (PHF) in neurofibrillary tangles (NFT). To analyze the relationship between the phosphorylation sites of tau and the activation of kinases in response to Abeta, we treated cultured rat hippocampal neurons with a peptide fragment of Abeta, Abeta(25-35). Abeta(25-35) treatment activated tau protein kinase I/glycogen synthase kinase-3beta (TPKI/GSK-3beta) but not glycogen synthase kinase-3alpha (GSK-3alpha) or mitogen activated protein kinase (MAP kinase) in primary culture of hippocampal neurons. Using antibodies that recognize phosphorylated sites of tau, we showed that tau phosphorylation was enhanced in at least five sites (Ser199, Ser202, Ser396, Ser404, and Ser413 numbered according to the human tau isoform containing 441 amino acid residues), to an extent that depended on the level of TPK I/GSK-3beta. Treatment with TPK I/GSK-3beta antisense oligonucleotide inhibited the enhancement of tau phosphorylation induced by Abeta(25-35) exposure. Thus, TPK I/GSK-3beta activation by Abeta(25-35) may lead to extensive tau phosphorylation.

The ultrastructural findings of Charcot-Leyden crystals in stroma of mastocytoma

Charcot-Leyden crystals (CLCs) have been found in many conditions associated with eosinophilia, but their occurrence in skin diseases is very rare. We report ultrastructural observations on the presence of CLCs in the cutaneous lesions of two cases of mastocytoma. Electron microscopy documented CLCs located in phagosomes of morphologically activated macrophages as well as free CLCs in the stromal tissue, close association between CLCs formation and damaged and lysed eosinophils was present. These findings provided evidence that the formation of CLCs in mastocytoma implicated the individual and interrelated biology of mast cells, eosinophils and macrophages. Phagosomes probably acted as the site of CLCs formation. The clinic and pathologic role of CLCs in mastocytoma deserves further investigation.

Longitudinal study of cerebrospinal fluid levels of tau, A beta1-40, and A beta1-42(43) in Alzheimer's disease: a study in Japan

To clarify the alterations of tau, amyloid beta protein (A beta) 1-40 and A beta1-42(43) in the cerebrospinal fluid (CSF) that accompany normal aging and the progression of Alzheimer's disease (AD), CSF samples of 93 AD patients, 32 longitudinal subjects among these 93 AD patients, 33 patients with non-AD dementia, 56 with other neurological diseases, and 54 normal control subjects from three independent institutes were analyzed by sensitive enzyme-linked immunosorbent assays. Although the tau levels increased with aging, a significant elevation of tau and a correlation between the tau levels and the clinical progression were observed in the AD patients. A significant decrease of the A beta1-42(43) levels and a significant increase of the ratio of A beta1-40 to A beta1-42(43) were observed in the AD patients. The longitudinal AD study showed continuous low A beta1-42(43) levels and an increase of the ratio of A beta1-40 to A beta1-42(43) before the onset of AD. These findings suggest that CSF tau may increase with the clinical progression of dementia and that the alteration of the CSF level of A beta1-42(43) and the ratio of A beta1-40 to A beta1-42(43) may start at early stages in AD. The assays of CSF tau, A beta1-40, and A beta1-42(43) provided efficient diagnostic sensitivity (71%) and specificity (83%) by using the production of tau levels and the ratio of A beta1-40 to A beta1-42(43), and an improvement in sensitivity (to 91%) was obtained in the longitudinal evaluation.

Combination assay of CSF tau, A beta 1-40 and A beta 1-42(43) as a biochemical marker of Alzheimer's disease

Cerebrospinal fluid samples from a total of 157 subjects consisting of 55 patients with sporadic Alzheimer's disease (AD), 34 normal controls, 23 patients with non-AD dementia, and 45 with other neurological diseases were examined by ELISA of tau, A beta 1-40, and A beta 1-42(43). The AD group had a significantly higher level of tau than the normal control group (P < 0.001), and the diagnostic sensitivity was 31% and specificity was 94%. CSF A beta 1-40 levels did not show any significant differences. Although the level of A beta 1-42(43) was decreased significantly in the AD group compared to the control group (P < 0.005), the overlap of A beta 1-42(43) levels among all groups meant that none of the AD samples exceeded the cut-off value, the mean 2SD of normal control subjects. Reduction of A beta 1-42(43) levels in AD resulted in a significant increase in the ratio of A beta 1-40 to A beta 1-42(43) (A beta ratio) as an improved marker. The diagnostic sensitivity and specificity of A beta ratio were 51% and 82% respectively. The three indexes, using the tau level and A beta ratio (tau or A beta ratio, deviation score and tau x A beta ratio), showed better sensitivity (58%, 67%, 69%) and specificity (82%, 86%, 88%) than previously reported methods. Combination assay for CSF tau, A beta 1-40 and A beta 1-42(43) in CSF is a biological marker of AD and may be useful to biochemically monitor subjects under treatment.

Characterization of tau phosphorylation in glycogen synthase kinase-3beta and cyclin dependent kinase-5 activator (p23) transfected cells

One of the histopathological markers in Alzheimer's disease is the accumulation of hyperphosphorylated tau in neurons called neurofibrillary tangles (NFT) composing paired helical filaments (PHF). Combined tau protein kinase II (TPK II), which consists of CDK5 and its activator (p23), and glycogen synthase kinase-3beta (GSK-3beta) phosphorylate tau to the PHF-form in vitro. To investigate tau phosphorylation by these kinases in intact cells, the phosphorylation sites were examined in detail using well-characterized phosphorylation-dependent anti-tau antibodies after overexpressing the kinases in COS-7 cells with a human tau isoform. The overexpression of tau in COS-7 cells showed extensive phosphorylation at Ser-202 and Ser-404. The p23 overexpression induced a mobility shift of tau, but most of the phosphorylation sites overlapped the endogenous phosphorylation sites. GSK-3beta transfection showed the phosphorylation at Ser-199, Thr-231, Ser-396, and Ser-413. Triplicated transfection resulted in phosphorylation of tau at 8 observed sites (Ser-199, Ser-202, Thr-205, Thr-231, Ser-235, Ser-396, Ser-404, and Ser-413).

Characteristics of cardiac hypertrophy in the juvenile visceral steatosis mouse with systemic carnitine deficiency

The juvenile visceral steatosis (JVS) mouse exhibits hereditary systemic carnitine deficiency and develops cardiac hypertrophy. The aim of this study was to clarify the characteristics of cardiac hypertrophy in the JVS mouse. Total carnitine content in IVS mouse heart was about 10% of that of control mouse heart at 4 and 8 weeks of age. The heart weight/body weight ratio was bigger in JVS mice than that in control mice at 2 weeks of age, and this difference in ratio increased with age. The wall areas of both ventricles and septum in JVS mice were larger than those of the control mice at 2 and 8 weeks. The myocyte diameter in both ventricular walls and septum in JVS mice was longer than that of the control mice. On electron microscopy, the percent of mitochondria in the myocyte was 66% in JVS mice, and 37% in control mice. The percent of lipid fraction in JVS mice was six-fold higher than that in control mice. Total content of adenine nucleotides in JVS mouse heart was about 60% of that in control mouse heart. Adenylate energy charge in JVS mouse heart was 63 and 45% of that in the control mouse heart at 4 and 8 weeks, respectively. Overall, the cardiac enlargement observed in this animal model could be accounted for by a proportional increase in the myocyte diameter in the ventricles and septum, accompanied by an increase in mitochondria. Furthermore, this cellular growth is associated with decreases in the levels of ATP and ADP, and adenylate energy charge.

Protein anatomy: C-tail region of human tau protein as a crucial structural element in Alzheimer's paired helical filament formation in vitro

Tau is a microtubule-associated protein in mammalian brain. In Alzheimer's disease, this protein is present in the somatodendritic compartment of certain nerve cells, where it forms a portion of paired helical filament, the major constituent of the neurofibrillary tangle. For clarification of the mechanism of this formation, recombinant human tau and its fragments (N-terminal half, C-terminal half, and 4-repeats) expressed in Escherichia coli were prepared, eight peptide fragments (C-tails 1-8) of the C-tail region were synthesized, and the conformation and capacity for aggregation essential for filamentous structure formation in vitro were examined. Recombinant full-length tau, the N-terminal half, 4-repeats, and the C-terminal half did not form filamentous structures in aqueous solution after standing at 20 degrees C. Peptides corresponding to the C-tail region of tau, C-tail 5, C-tail 7, and C-tail 8, produced the paired filament or single straight filament in acidic solution. The rate of filament formation by each peptide was followed by circular dichroism, which showed the C-tails to have predominantly random coil structures immediately following dissolution in aqueous solution and be gradually converted to the beta-sheet structure. The kinetics of aggregation were characterized by a delay period during which the solution remained clear, followed by a nucleation event which led to a growth phase, whose negative peak intensity at 218 nm in circular dichroism increased due to filamentous structure formation. This delay was eliminated by seeding supersaturated solution of preformed filaments. C-tails interacted with recombinant full-length tau to form definite single straight filament. The C-tail region of tau is thus shown indispensable to the formation of paired helical filament and nucleation to reduce the rate of paired helical filament formation in amyloidogenesis in vitro. These findings may provide some clarification of the pathogenesis of Alzheimer's disease.

Production of toxic shock syndrome toxin by Staphylococcus aureus isolated from mastitic cow's milk and farm bulk milk

The production of toxic shock syndrome toxin (TSST) by Staphylococcus aureus isolated from mastitic cow's milk and farm bulk milk was examined by a reverse passive latex agglutination method (RPLA). TSST was detected in 25 (58.1%) of 43 isolates from clinical mastitic cow's milk, in 79 (76.7%) of 103 isolates from subclinical mastitic cow's milk, and in 95 (75.4%) of 126 isolates from farm bulk milk, respectively. When the quantity of TSST in the isolates was determined by RPLA, the titers ranged from 5 to 2560. TSST with RPLA titers of 640 to 2,560 was produced by 83 (30.5%) of 272 isolates tested. Almost all of the isolates showing RPLA titers of 640 and over produced enterotoxin C, whereas isolates showing titers of 5 to 320 produced enterotoxin C or both enterotoxin A and C. SDS-polyacrylamide gel electrophoresis and isoelectric focusing with immunoblotting showed that the TSST from bovine isolates had same molecular size (22 kDa) and isoelectric point (7.2) as TSST-1 from human isolates. These findings are consistent with previous reports.

Footprint analysis of the RAG protein recombination signal sequence complex for V(D)J type recombination

We have studied the interaction between recombination signal sequences (RSSs) and protein products of the truncated forms of recombination-activating genes (RAG) by gel mobility shift, DNase I footprinting, and methylation interference assays. Methylation interference with dimethyl sulfate demonstrated that binding was blocked by methylation in the nonamer at the second-position G residue in the bottom strand and at the sixth- and seventh-position A residues in the top strand. DNase I footprinting experiments demonstrated that RAG1 alone, or even a RAG1 homeodomain peptide, gave footprint patterns very similar to those obtained with the RAG1-RAG2 complex. In the heptamer, partial methylation interference was observed at the sixth-position A residue in the bottom strand. In DNase I footprinting, the heptamer region was weakly protected in the bottom strand by RAG1. The effects of RSS mutations on RAG binding were evaluated by DNA footprinting. Comparison of the RAG-RSS footprint data with the published Hin model confirmed the notion that sequence-specific RSS-RAG interaction takes place primarily between the Hin domain of the RAG1 protein and adjacent major and minor grooves of the nonamer DNA.

Accumulation of amyloid beta protein in transgenic mice

Carboxyl-terminal fragments of beta amyloid precursor protein (betaAPP) were expressed in mice under the transcriptional control of an ubiquitous promoter system, based upon a chicken beta-actin (betaA) promoter combined with cytomegalovirus (CMV) enhancer to obtain a systemic overproduction of amyloid beta protein (Abeta). Three transgene constructs were designed to encode signal peptide and carboxyl-terminal 99 amino acid residues to betaAPP (NOR-beta), methionine and C-terminal 103 amino acid residues of betaAPP (deltaNOR-beta), and methionine and C-terminal 103 amino acid residues with KM-NL substitution of betaAPP (deltaNL-beta). Although the transcriptional mRNA level and post-translational protein level from transgenes showed the same expression pattern, both the expression of Abeta and distribution of Abeta deposits were completely different among these strains. In NOR-beta mice, considerable amounts of Abeta were detected in plasma and Abeta deposits were observed in the pancreas. Brain Abeta deposits and small amounts of plasma Abeta were recognized in deltaNL-beta. These findings indicate that tissue specific processing and transgene constructs are major factors to determine the distribution of Abeta deposits.

Immunocytochemistry of formalin-fixed human brain tissues: microwave irradiation of free-floating sections

Formalin fixation, the chemical process in which formaldehyde binds to cells and tissues, is widely used to preserve human brain specimens from autolytic decomposition. Ultrastructure of cellular and mitochondrial membranes is markedly altered by vesiculation, but this does not interfere with diagnostic evaluation of neurohistology by light microscopy. Serious difficulties are encountered, however, when immunocytochemical staining is attempted. Antigens that are immunoreactive in unfixed frozen sections and protein extracts appear to be concealed or destroyed in formalin-fixed tissues. In dilute aqueous solution, formaldehyde is in equilibrium with methylene glycol and its polymeric hydrates, the balance by far in favor of methylene glyco. Carbonylic formaldehyde is a reactive electrophilic species well known for crosslinking functional groups in tissue proteins, nucleic acids, and polysaccharides. Some of its methylene crosslinks are readily hydrolyzed. Others are stable and irreversible. During immunostaining reactions, intra- and inter-molecular links between macromolecules limit antibody permeation of tissue sections, alter protein secondary structure, and reduce accessibility of antigenic determinants . Accordingly, immunoreactivity is diminished for many antigens. Tissues are rapidly penetrated by methylene glycol, but formaldehyde binding to cellular constituents is relatively slow, increasing progressively until equilibrium is reached. In addition, prolonged storage in formalin may result in acidification of human brain specimens. Low pH favors dissociation of methylene glycol into formaldehyde, further reducing both classical staining and antigen detectability. Various procedures have been devised to counter the antigen masking effects of formaldehyde. Examples include pretreatment of tissue sections with proteases, formic acid, or ultrasound. Recently, heating of mounted sections in ionic salt solution by microwave energy was found to restore many antigens. Theory and practice of microwave antigen retrieval are covered extensively in the handbook Microwave Cookbook for Microscopists. A concise overview of microwave methods in the neurosciences has been published, and clinical applications have been reviewed. In this context, it should be noted that fresh tissues may be stabilized for immunocytochemistry by reversible, non-chemical binding processes such as cryosectioning after microwave treatment and freeze-drying. Thus, it may be possible to enhance immunostaining for some antigens by microwave irradiation of unfixed as well as fixed specimens. Parameters to be optimized for microwave retrieval of specific antigens include temperature, irradiation time, tissue buffer composition, salt concentration, and pH. Temperature, irradiation time, and pH are key variables. With this in mind, an optimal method was developed for retrieval of a wide variety of antigens in human brain tissues. Typical microwave protocols employ elevated temperatures that may reach 100 degrees C, where denaturation causes irreversible uncoiling and disruption of protein secondary and tertiary structures. Under these conditions, stable covalent bonds securing methylene crosslinks between polypeptides remain intact, but more reactive links formed by Schiff bases may be hydrolyzed. Resultant conformational changes presumably expose buried loops of continuous amino acids and protruding regions, increasing accessibility of their epitopes. Protein denaturation seems to be a reasonable explanation for the effects of microwaves on antigen retrieval. This idea is supported by the observation that denaturing solutions such as 6 M urea increase immunoreactivity of some antigens. Still, the molecular basis of these effects remains unresolved, in part due to the complex chemistry of formaldehyde reactions with tissue constituents. Indeed, some methylene bridges between similar groups such as NH2 and NH may be hydrolyzed by washing fixed tissues in distilled wa

Possible role of tau protein kinases in pathogenesis of Alzheimer's disease

Tau protein kinases (TPK) I and II were isolated as candidate enzymes responsible for the hyperphosphorylation observed in PHF-tau. Four phosphorylation sites of tau were identified for each kinase, accounting for most, but not all, of the major phosphorylation sites of PHF-tau. Immunostaining with anti-TPKI antibody indicated that this kinase is up-regulated in AD brain. Such up-regulation of TPKI and phosphorylatioin of tau were reproduced by treating cultured hippocampal cells with amyloid beta (Abeta) protein. In addition, we found that TPKI can phosphorylate and inactivate pyruvate dehydrogenase (PDH), which is expected to result in depletion of acetyl-CoA, a key substrate of acetyl choline synthesis. Indeed, when septum cells were treated with Abeta, the level of acetyl choline decreased dramatically.

Apolipoprotein E accumulates with the progression of A beta deposition in transgenic mice

To study the role of apolipoprotein E (apoE) in vivo in deposits of amyloid beta protein (A beta), a major component of senile plaque amyloid in the brain of patients with Alzheimer disease, the transgenic mice were examined by apoE immunostaining. The mice were systemically overexpressing signal peptide and 99 amino acid residues of the carboxy-terminal fragment of human amyloid beta protein precursor (betaAPP) under control of the powerful cytomegalovirus enhancer/chicken beta-actin promotor. A beta deposits appeared at 4 months and increased with aging in the acinar cells of the transgenic pancreas. Similarly, apoE deposits appeared in the pancreatic acinar cells at 4 months old. The number and size of apoE deposits increased with aging and correlated with the progression of A beta deposits. Interstitial macrophages labeled by apoE immunostaining appeared at 8 months after birth and their number increased with aging. On serial section of the pancreata of 24-month-old mice, approximately 70% of A beta deposits were labeled with the apoE antiserum. ApoE was detected in the highly insoluble formic acid fraction of the transgenic pancreas by an immunoblot study. The Northern blot study revealed no increase in synthesis of endogenous apoE mRNA. These findings indicate that apoE is closely related to progression of A beta deposits with aging and suggest that A beta deposition in the transgenic pancreas is similar to that in the senile plaque of Alzheimer brains. Therefore, our experimental system using transgenic mice will provide a useful tool to analyze the molecular mechanism of A beta deposition in association with apoE in vivo.

Clonal variability in beta-globin mRNA content in an interleukin-3-dependent bone marrow cell line transfected with the erythropoietin receptor before and after stimulation with erythropoietin

Unexpected clonal variability was observed in the content of beta-globin mRNA in erythropoietin receptor (EpoR)-transfected Ba/F3 cells before and after exposure to erythropoietin (Epo). Of 11 clones selected by virtue of G418 resistance and positive EpoR expression, 5 clones showed high levels of beta(major)-globin mRNA before Epo exposure, with subsequent Epo treatment causing little or no increase in globin mRNA. Five clones had undetectable levels of globin mRNA before Epo stimulation, and they did not accumulate globin mRNA when exposed to Epo, exhibiting resistance to the differentiation inducing action of Epo. Only one clone exhibited the expected phenotype, a low level of globin mRNA before exposure to Epo, and a significant Epo-dependent accumulation of globin mRNA. Phosphorylation of tyrosyl residues of the EpoR, Stat5, and JAK2 occurred upon Epo stimulation in clones representing each category. Furthermore, electrophoretic mobility shift assays using a Stat5 consensus sequence showed a difference in the nuclear binding component among these clones. These findings indicate that (1) the attainment of EpoR+ Ba/F3 clones with the anticipated sensitivity to both the growth and differentiation inducing actions of Epo is a rare event and (2) STAT5 transcription factors were differently activated by Epo in clones that differed in sensitivity to Epo.

Lysosomal generation of amyloid beta protein species in transgenic mice

Soluble amyloid beta protein (A beta)1-40 and highly amyloidogenic A beta 1-42/43 were immunocytochemically labeled in lysosomes of acinar cells and macrophages in the pancreas of transgenic mice systemically expressing a C-terminal fragment of the A beta precursor. A beta 1-42/43 and long A beta species extending their C-termini were detected in the detergent-insoluble fraction. Immunoreactivity of cathepsin D was markedly increased in lysosomes filled with A beta fibrils. These findings indicated that A beta 1-40, A beta 1-42, A beta 1-43 and longer A beta species were generated in the lysosomes of the transgenic pancreas, and suggested that the activation of cathepsin D, a candidate gamma-secretase, leads to acceleration of A beta amyloid formation.

[A case of successful endoscopic treatment for traumatic bronchial rupture]

Successful endoscopic treatment with fibrin glue for traumatic bronchial rupture was reported. 21-year-old male, who was injured in a traffic accident was brought to ICU in our hospital. Six days after injury, bronchoscopic findings showed a rupture from right truncus intermedius to lower bronchus (B8). We preferred an endoscopic treatment with fibrin glue because of poor respiratory function caused by lung contusion as a complication and those resulted in successfully healing. In general, basic strategy for traumatic bronchial rupture is the earlier diagnosis and surgical treatment. But in a case of high risk for operation, we recommend endoscopic treatment with fibrin glue might be useful.

[Anticancer drug-induced colitis--case report and review of the literature]

We encountered two chemotherapy cases related to anticancer drug-induced colitis. Case 1 was a 35-yo-female with a recurrence of ovarian cancer. She was treated with intraarterial infusion consisting of continuous 5-fluorouracil (250 mg/day 5 days/week x 4) following low-dose consecutive cisplatin (20 mg/day 5 days/ week x 1). The catheter was inserted into the abdominal aorta about 2 cm above the carina of the common iliac arteries. Six weeks after the start of chemotherapy, severe abdominal pain and melena occurred. Case 2 was a 68-yo-female with an endometrial cancer recurrence. The same intraarterial chemotherapy used in case 1 was was initiated. Four weeks after the start of chemotherapy, before intraarterial infusion of CDDP, she suffered from constipation and than diarrhea, abdominal pain and melena. Both cases were diagnosed as anticancer drug-induced colitis with the pathological findings from colon biopsy and the clinical course, and improved in about 1 month with the discontinuation of intraarterial infusion, fasting and TPN. Intraarterial infusion of only CDDP caused both patients no intestinal symptoms, so it is supposed that intraarterial infusion of 5-fluorouracil induced the colitis. Anticancer drug-induced colitis should be taken into consideration as a rare but possible course of chemotherapy-related complication with intraarterial infusion of 5-fluorouracil.

[Four cases of subpleural intrapulmonary lymph node]

We presented four cases of subpleural intrapulmonary lymph node showing the indeterminate pulmonary nodule. Case 1 was a 54-year-old male who had a subpleural nodule, 7 mm in diameter in the right S8 segment on chest CT. This nodule showed difficulty to differentiate from small peripheral lung carcinoma. Case 2 was a 72-year-old male who was diagnosed adenocarcinoma of lung. Chest CT showed multiple pulmonary nodules, about 5 mm in diameter except main tumor in the right middle and lower lobes. These nodules showed difficulty to differentiate from intrapulmonary metastasis. Case 3 was a 70-year-old female who was diagnosed lung metastasis of sigmoid colon cancer. Chest CT showed a subpleural nodule, 3 mm in diameter except main tumor in the right S9 segment. This nodule also showed difficulty to differentiate from lung metastasis. Case 4 was a 40-year-old female who had a subpleural nodule, 10 mm in diameter in the right S9 segment. This nodule also showed difficulty to differentiate from small peripheral lung carcinoma. We diagnosed subpleural intrapulmonary lymph nodes, in case 1, 2 and 3, by open thoracotomy and in case 4, thoracoscopic surgery. It should be always kept in mind that subpleural pulmonary nodules in especially middle and lower lobes of lung might be intrapulmonary lymph nodes. Thoracoscopic surgery would be a very useful procedure for diagnosis and therapy of subpleural intrapulmonary lymph nodes.

[Surgical treatment and result for metastatic pulmonary tumor: comparison between sarcoma and carcinoma]

Purpose of this study is to estimate the effectiveness of surgical treatment for metastatic pulmonary tumor by comparing sarcoma with carcinoma. There ware 43 cases and 64 operations of metastatic pulmonary tumor from 1981 to 1995 in Tottori university hospital. When we compared the background factors between sarcoma and carcinoma, there were significant differences in age, numbers of metastatic tumor and times of operation. Patients of sarcoma were much younger and had more number of metastatic tumor and more times of operation than those of carcinoma. Long term results after operation were 50.8% at 5 years and 44.4% at 10 years survival rate in all cases. The 5 year survival rate of sarcoma (38.1%) had a tendency of worse result than that of carcinoma (57.3%). Important factors that influence the post operative long term result were more numbers of pulmonary metastasis and more times of operation in sarcoma. On the other hand, because cases of carcinoma included many low grade malignancies in the group of multiple metastasis, the postoperative result of multiple metastasis became relatively better in our study.

Nontoxic amyloid beta peptide 1-42 suppresses acetylcholine synthesis. Possible role in cholinergic dysfunction in Alzheimer's disease

We show here that amyloid beta peptide1-42 (Abeta1-42) may play a key role in the pathogenesis of the cholinergic dysfunction seen in Alzheimer's disease (AD), in addition to its putative role in amyloid plaque formation. Abeta1-42 freshly solubilized in water (non-aged Abeta1-42), which was not neurotoxic without preaggregation, suppressed acetylcholine (ACh) synthesis in cholinergic neurons at very low concentrations (10-100 nM), although non-aged Abeta1-40 was ineffective. Non-aged Abeta1-42 impaired pyruvate dehydrogenase (PDH) activity by activating mitochondrial tau protein kinase I/glycogen synthase kinase-3beta, as we have already shown in hippocampal neurons (Hoshi, M., Takashima, A., Noguchi, K., Murayama, M., Sato, M., Kondo, S., Saitoh, Y., Ishiguro, K., Hoshino, T., and Imahori, K. (1996) Proc. Natl. Acad. Sci. U. S. A. 93, 2719-2723). Neither choline acetyltransferase activity nor choline metabolism was affected. Therefore, the major cause of reduced ACh synthesis was considered to be an inadequate supply of acetyl-CoA owing to PDH impairment. Soluble Abeta1-42 increases specifically in AD brain (Kuo, Y.-M., Emmerling, M. R., Vigo-Pelfrey, C., Kasunic, T. C., Kirkpatrick, J. B., Murdoch, G. H., Ball, M. J., and Roher, A. E. (1996) J. Biol. Chem. 271, 4077-4081). This increase in soluble Abeta1-42 may disturb cholinergic function, leading to the deterioration of memory and cognitive function that is characteristic of AD.

The response of IL-3 dependent B6SUtA bone marrow cells to both erythropoietin and chemical inducers of differentiation

To develop cell lines which respond to both a physiological cytokine and chemical agents by the induction of differentiation pathway, factor dependent B6SUtA murine bone marrow cells were transfected with the erythropoietin receptor (EpoR). Clones were obtained that exhibited different sensitivities to erythopoietin (Epo), with one clone exhibiting erythroid differentiation in response to Epo, while in another Epo acted as a proliferation stimulus. Moreover, parental B6SUtA cells were sensitive to the initiation of differentiation by butyrate, diazepam and hemin. Thus, B6SUtA cells appear to represent a unique model to dissect the signaling molecules involved in the growth and differentiation pathways employed by Epo and non-physiological chemicals.

Detection of toxic shock syndrome toxin-1 gene in Staphylococcus aureus bovine isolates and bulk milk by the polymerase chain reaction

Staphylococcus aureus isolates from mastitic cow's milk and farm bulk milk were examined for toxic shock syndrome toxin-1 (TSST-1) gene (tst gene) by the polymerase chain reaction (PCR). The 179 bp band of tst gene was observed in almost all the bovine isolates which showed TSST positive in a latex agglutination, as well as in human strain FRI 1169, but was not observed in bovine isolates of TSST negative. The lowest detectable threshold of the PCR for tst gene was 1.2 x 10(3) cells/ml. When 125 bovine milk samples were cultured selectively for staphylococci and examined by PCR, the tst gene was detected in 10 of the 35 culture fluids, in which staphylococci were recognized by Gram's staining.

Immunocytochemistry of tau phosphoserine 413 and tau protein kinase I in Alzheimer pathology

One unique phosphorylation site consistently found in paired helical filament tau, serine 413, is modified by tau protein kinase I/glycogen synthase kinase-3 beta but no other known tau kinase. Here we present immunocytochemistry from Alzheimer's disease brains showing that focal subpopulations of hippocampal CA1 pyramidal neurons and neuritic plaques are strongly reactive for tau protein kinase I/glycogen synthase kinase-3 beta and tau phosphoserine 413 in early stages of pathology. Colocalization of these epitopes suggests that tau protein kinase I/glycogen synthase kinase-3 beta abnormally phosphorylates tau and is in a position to disrupt neuronal metabolism in anatomical areas vulnerable to Alzheimer's disease.