Impaired neurotransmitter systems by Abeta amyloidosis in APPsw transgenic mice overexpressing amyloid beta protein precursor

APPsw transgenic mice showing substantial features of brain Abeta amyloidosis such as senile plaques and behavioral abnormalities were examined by immunostaining to determine whether Abeta deposits could induce the subsequent disturbance of neurotransmitter systems including somatostatin, substance P and choline acetyltransferase (ChAT), which are prominent in the Alzheimer's disease brain. Somatostatin, substance P and ChAT disappeared in the areas of senile plaque and were accumulated in dystrophic neurites around the amyloid cores. These findings suggest a potential role of brain Abeta amyloidosis in disturbance of the neurotransmitter systems leading to memory disturbance of Alzheimer's disease.

A morphological and morphometrical study of the retina in aging SAM mice

We investigated whether neuronal cell loss occurred as a part of normal aging of the retina in the Senescence-Accelerated Mouse, strains SAMP1 and SAMR1, and in the BALB/c mouse. All three strains showed age-related atrophy of the retina after histologically normal development. Morphometrical study revealed the following facts. The rate of loss of photoreceptor cells in the peripheral retina was greater than in the central retina in all three strains. In the central retina, the rate of loss of photoreceptor cells was greater in the SAMP1 and SAMR1 mice than in the BALB/c mice. In the peripheral retinal, the SAMR1 and SAMP1 strains had fewer cells than the BALB/c strain at all ages, but the rate of loss of these cells did not differ among the three strains. The rate of loss of ganglion cells did not differ between the peripheral and central retinas in the three strains. The SAMR1 and SAMP1 strains had fewer ganglion cells in the peripheral retina than the BALB/c strain at all ages. Because the rate of age-related loss of these cells in SAMP1 mice was not accelerated, and they were short-lived, SAMP1 mice did not show marked age-related loss. On the contrary, the SAMR1 mice showed a marked loss of photoreceptor cells and ganglion cells late in life because of their longer life span, and we propose that this strain is a suitable animal model for the study of mechanisms of age-related loss of neuronal cells in the retina.

Amyloid beta protein starting pyroglutamate at position 3 is a major component of the amyloid deposits in the Alzheimer's disease brain

The amyloid beta protein (Abeta) deposited in the Alzheimer's disease (AD) brain is heterogeneous at both its amino and carboxyl termini. Recent studies of the genetic forms of AD indicate that the aggregation and deposition of Abeta42 may be a common initiating event in all forms of AD. Here, we analyzed the amino termini of the Abeta species deposited in the AD brain, focusing specifically on species with amino-terminal pyroglutamate at position 3 (Abeta3(pE)). Immunocytochemical analysis of AD brains with an antibody specific for Abeta3(pE) confirmed that these species deposit in blood vessels and senile plaques. Using specific sandwich ELISAs, we determined the amounts of Abeta3(pE)-40 and Abeta3(pE)-42(43) in AD brain compared with other forms. This analysis showed that Abeta3(pE)-40 is closely correlated with the extent of Abeta deposition in blood vessels, whereas Abeta3(pE)-42(43) is not. In addition, Abeta3(pE)-42(43) is an important component of the Abeta deposited in senile plaques of the AD brain, constituting approximately 25% of the total Abeta42(43). In vitro comparison of Abeta1-42 and Abeta3(pE)-42 showed that Abeta3(pE)-42 is highly prone to oligomerization. These findings suggest that Abeta3(pE)-42 may be particularly important in AD pathogenesis.

Angiomyomatous hamartoma and associated stromal lesions in the right inguinal lymph node: a case report

Angiomyomatous hamartoma is a rare disease with a predisposition for the inguinal lymph nodes. A 51-year-old male patient visited a local hospital because of a right inguinal mass, measuring 3 x 4 cm in size, which was resected. The resected specimen showed irregularly distributed thick-walled vessels in the hilum, extending into the medulla and focally into the cortex of the node, eventually becoming more dispersed and associated with smooth muscle cells splaying into sclerotic stroma. These findings are compatible with an angiomyomatous hamartoma. Another tumor-like mass appeared shortly after the resection at the same location, but was not an angiomyomatous hamartoma, rather it was composed of edematous stromal tissue with proliferating smooth muscle cells. The stromal component included thick-walled blood vessels and lymphatics. Although it could not be determined whether these associated changes in the surrounding stroma are a cause or an effect of angiomyomatous hamartoma, they indicate the clinical difficulty in determining an appropriate area of resection and may provide clues to the pathogenesis of angiomyomatous hamartoma.

Fibrillar amyloid-beta production, accumulation, and recycling in transgenic mice pancreatic acinar cells and macrophages

Amyloid-beta (A beta) production, accumulation, and recycling were examined by light and electron microscopy in the pancreas of transgenic mice (from 45 days to 22 months of age) that express the gene for the carboxy-terminal fragment of the human amyloid-beta protein precursor. Ultrastructural immunocytochemistry revealed four types of cells accumulating fibrillar A beta 1-40 in cytoplasmic vacuoles: acinar pancreatic cells, macrophages infiltrating stroma, epithelial cells of pancreatic ducts, and blood monocytes/macrophages in the lumen of pancreatic vessels. The ultrastructure of amyloid deposits suggests that each of these four types of cells produces fibrillar A beta. Three basic types of amyloid deposits were distinguished: primary vacuoles in different stages of amyloid aggregation and fibrillization, secondary vacuoles that are the product of fusion of primary vacuoles, and phagosome-like vacuoles with morphologically intact fibrillar amyloid and residues of ingested cells. Amyloid production in acinar pancreatic cells starts in mice younger than 45 days, progresses in 2- to 7-month-old mice, and plateaus in the second year of life. In macrophages, amyloid appears in 60-day-old mice, and the increase in the number of macrophages and the amount of amyloid in their cytoplasm correlates with age.

Positive association of endothelial nitric oxide synthase gene polymorphism with hypertension in northern Japan

Vascular endothelial cells produce nitric oxide (NO), which contributes to the regulation of blood pressure and regional blood flow. Although Endothelial NO synthase (eNOS) gene polymorphisms have been shown to have a positive association with coronary artery disease, the linkage between eNOS gene polymorphisms and hypertension has been controversial. In the present study, therefore, we identified genotypes for Glu298Asp and variable number tandem repeats in intron 4 (4b/a) in 183 hypertensive and 193 normotensive populations. The Glu298Asp variant had a significant association with hypertension (odds ratio, 1.8; 95% confidence interval, 1.1-3.0). The allele frequencies of 298Asp for Glu298 in hypertensive patients were significantly higher than those in normotensive subjects (0.128 vs 0.080, p<0.05). Diastolic and mean arterial blood pressures were significantly higher in hypertensive subjects with the 298Asp allele than those without the variant allele (p<0.05). However, disequilibrium of 4b/a polymorphism was absent between these two groups. These results suggest that the Glu298Asp variant may be a genetic susceptibility factor for hypertension.

Accumulation of NACP/alpha-synuclein in lewy body disease and multiple system atrophy

OBJECTIVES

NACP/alpha-synuclein is an aetiological gene product in familial Parkinson's disease. To clarify the pathological role of NACP/alpha-synuclein in sporadic Parkinson's disease and other related disorders including diffuse Lewy body disease (DLBD) and multiple system atrophy (MSA), paraffin sections were examined immunocytochemically using anti-NACP/alpha-synuclein antibodies.

METHODS

A total of 58 necropsied brains, from seven patients with Parkinson's disease, five with DLBD, six with MSA, 12 with Alzheimer's disease, one with Down's syndrome, one with amyotrophic lateral sclerosis (ALS), three with ALS and dementia, one with Huntington's disease, two with progressive supranuclear palsy (PSP), one with Pick's disease, one with myotonic dystrophy, and three with late cerebellar cortical atrophy (LCCA), and 15 elderly normal controls were examined.

RESULTS

In addition to immunoreactive Lewy bodies, widespread accumulation of NACP/alpha-synuclein was found in neurons and astrocytes from the brainstem and basal ganglia to the cerebral cortices in Parkinson's disease/DLBD. NACP/alpha-synuclein accumulates in oligodendrocytes from the spinal cord, the brain stem to the cerebellar white matter, and inferior olivary neurons in MSA. These widespread accumulations were not seen in other types of dementia or spinocerebellar ataxia.

CONCLUSION

Completely different types of NACP/alpha-synuclein accumulation in Parkinson's disease/DLBD and MSA suggest that accumulation is a major step in the pathological cascade of both diseases and provides novel strategies for the development of therapies.

Age-related amyloid beta protein accumulation induces cellular death and macrophage activation in transgenic mice

In view of the importance of amyloid beta protein accumulation in Alzheimer's disease, this paper examines age-related amyloid beta protein (Abeta) deposition and accompanying cellular changes in a mouse model in vivo. Transgenic mice were studied which expressed a gene encoding 18 residues of signal peptide and 99 residues of the carboxyl-terminal fragment (CTF) of the Abeta precursor, under the control of the cytomegalovirus enhancer/chicken beta-actin promoter. In the pancreas, Abeta accumulated in an age-dependent manner. Abeta deposits appeared as early as 3 weeks of age and increased in size and number from 4 to 16 months of age. The largest Abeta deposits were observed in the transgenic pancreas at 16 and 20 months of age. Haematoxylin and eosin staining, macrophage immunostaining, and electron microscopy showed that the Abeta fibril deposits closely correlated with degeneration of pancreatic acinar cells and macrophage activation. Abeta1-42 and Abetap3E-42 were predominant components of Abeta deposits among amino- and carboxyl-terminal modified Abeta species. These findings suggest that overproduction of Abeta causes age-related accumulation of Abeta fibrils, with accompanying cellular degeneration and macrophage activation in vivo.

Simultaneous suppression of cdc2 and cdk2 activities induces neuronal differentiation of PC12 cells

The involvement of cdc2 and cdk2 during neuronal differentiation in rat pheochromocytoma PC12 cells was examined. When PC12 cells were cultured with nerve growth factor (NGF), expression of cdc2 decreased significantly after day 5, while expression of cdk2 decreased gradually after day 7. Cells overexpressing cdc2 or cdk2 were resistant to NGF-induced differentiation and growth suppression, and maintained high cdc2 or cdk2 kinase activity, respectively, during NGF treatment. In contrast, the NGF-treated parental cells showed a marked decline in these kinase activities after day 3. When PC12 cells were treated with specific inhibitors of cdc2/cdk2 (butyrolactone-I, olomoucin), they showed marked neurite extension and up-regulation of microtubule-associated protein 2 expression. In addition, treatment with mixtures of antisense oligonucleotides for cdc2 and cdk2 resulted in down-regulation of both cdc2 and cdk2 kinase activities as well as significant neurite outgrowth and up-regulation of microtubule-associated protein 2 expression. However, neurite outgrowth was not observed in cells treated with either single antisense oligonucleotide, or antisense cdc2 + cdk4 or cdk2 + cdk4 oligonucleotide mixtures. These results suggest that simultaneous down-regulation of cdc2 and cdk2 activity is sufficient and necessary for neuronal differentiation in PC12 cells.

cDNAs encoding the baboon thrombin receptor indicate a primate transcription start site upstream of putative sites reported for the human gene

Two cDNAs encoding the thrombin receptor of baboon vascular smooth muscle cells have 5'-untranslated regions that begin upstream of multiple putative transcription initiation sites reported for the closely related human receptor gene. The extent of these baboon 5'-untranslated cDNA regions and their close similarity to the corresponding human sequences suggest that there is only one transcription initiation site of the primate thrombin receptor gene, which might be linked to a typical TATA-box previously identified in the upstream region of the human gene. It is possible that all primates have a unique thrombin receptor gene transcription start site. Inferences drawn from the baboon system may be usefully extrapolated to the human, in view of the extensive similarities seen between the nucleotide sequences of baboon and human thrombin receptor gene sequences in the 5'- untranslated and coding regions. The extents of the 5'-untranslated region of the baboon cDNAs argue that the "multiple" transcription start sites identified for the human gene are artifactual. The striking differences in the reported baboon and human transcription start sites warrant further investigation in view of the significant role played by the thrombin receptor in numerous vascular and cellular growth responses.

AT-1015, a novel serotonin (5-HT)2 receptor antagonist, blocks vascular and platelet 5-HT2A receptors and prevents the laurate-induced peripheral vascular lesion in rats

The serotonin (5-HT2A) antagonistic activities and the protective effect on laurate-induced peripheral vascular lesions of AT-1015, a novel 5-HT2 receptor antagonist, were investigated. In platelet aggregation, AT-1015 selectively inhibited in vitro 5-HT2A receptor-mediated aggregation, and the activity was almost equivalent to that of ketanserin (5-HT2A/2C receptor antagonist) and 100 times more potent than sarpogrelate (5-HT2A receptor antagonist). AT-1015 also inhibited 5-HT2A receptor-mediated aggregation by oral administration in rat, and the dose required for inhibition was equivalent to ketanserin. In a 5-HT-induced vasoconstriction study in rat, AT-1015 slightly reduced maximal contraction and caused a rightward shift of the concentration-response curve (pKB value, 9.5), which was unlike competitive inhibitors such as ketanserin and sarpogrelate (pA2 value, 9.3 and 8.7, respectively). Moreover, the ex vivo inhibitory activity significantly remained after oral administration (1 mg/kg). In the rat peripheral vascular lesion model, AT-1015 (1 mg/kg, p.o.) effectively prevented progression of peripheral lesions, and it was more potent compared with ketanserin, sarpogrelate, and cilostazol. These results suggest that AT-1015 is a potent 5-HT2A receptor antagonist, and its insurmountable antagonism may be relevant to its therapeutic potential in peripheral vascular disease.

Molecular and clinical analyses of spinocerebellar ataxia type 8 in Japan

OBJECTIVE

To clarify the molecular and clinical features of the newly identified spinocerebellar ataxia type 8 (SCA8).

METHODS

We analyzed the CTG repeat region of the SCA8 gene in a series of Japanese patients with cerebellar ataxia. We also investigated the frequency of the CTG repeat length in Japanese normal elderly subjects older than age 79. Morphometric measurements on the cerebral MRI were compared between patients with SCA8 and SCA6.

RESULTS

The number of the combined CTA/CTG repeats of six affected SCA8 alleles was 106.3+/-24.4 (mean +/- SD) ranging from 89 to 155 and that of normal elderly subjects was 24.3+/-4.4 (n = 104 alleles) ranging from 15 to 34. The mean age at onset of the SCA8 cases was 53.8+/-19.7 years, with a range from 20 to 73 years. One father and daughter from an SCA8 family showed remarkable paternal anticipation. The number increase from father to daughter was + 16 CTG repeats, with a 31-year acceleration of onset. The six identified SCA8 patients were clinically characterized by high frequencies of incoordination of trunk and limbs, ataxic dysarthria, impaired smooth pursuit, and horizontal nystagmus, and the MRI showed significant atrophy of the cerebellar vermis and hemispheres compared with that of normal controls. There was no significant difference between SCA8 and SCA6 on the morphometric MRI study.

CONCLUSIONS

The CTG repeat expansions in the SCA8 alleles were much greater than the range of repeats in normal elderly subjects. The SCA8 phenotype manifested by cerebellar symptoms and atrophy corresponded to features of the autosomal dominant cerebellar ataxia type III (ADCA III).

Distribution of amyloid beta protein precursor in the Alzheimer's disease brain

In order to clarify the distribution and pathological changes of the amyloid beta protein precursor (betaAPP), 10 Alzheimer's disease (AD) brains and seven normal control brains were examined by immunocytochemistry and in situ hybridization histochemistry. All betaAPP isoforms were distributed evenly in neuronal cell bodies and their axons and dendrites. The betaAPP-positive neuronal processes showed mesh-like networks. In AD brains, betaAPP-positive neurons and mesh-like networks were generally decreased in spite of some intensely labeled neurons. All betaAPP isoforms accumulated in neuronal processes, dystrophic neurites and senile plaques. In situ hybridization histochemistry confirmed that all isoforms of betaAPP were expressed in neurons in control brains. In AD brains, the betaAPP mRNA signal was generally decreased besides some intense signal neurons corresponding to immunostaining findings. Few astrocytes expressed betaAPP. Thus, uniform expression and distribution of betaAPP were disturbed in AD brains showing uneven decreases or increases of neuronal betaAPP expression in individual neurons and betaAPP accumulation in neurons, neuronal processes and abnormal structures including dystrophic neurites, senile plaques and neurofibrillary tangles.

Angiotensin-converting enzyme genotype is associated with Alzheimer disease in the Japanese population

We compared the distribution of an insertion (I)/deletion (D) polymorphism of the gene coding for the angiotensin-converting enzyme (ACE) in 133 Japanese sporadic Alzheimer disease (AD) patients with 257 controls. The association between AD and ACE genotypes or alleles was found to be significant. The frequency of II genotypes was 1.4 times higher in AD than controls, while that of DD genotypes was only 0.4 times as high. The altered distribution of ACE alleles in patients with AD appeared to be independent of apolipoprotein E.

[Water metabolism and its disturbances]

The central and peripheral mechanisms regulate body water balance near an ideal set point. Osmosensitive neurons in the organum vasculosum lamina terminalis (OVLT) in the anterior hypothalamus play a key role in regulating vasopressin release and drinking behaviour. Patients with OVLT lesions are known to have osmostat fluctuations. Although the brain water channel is suggested to participate in osmoreception, the precise molecular mechanisms of osmoreception and thirst appreciation remain to be clarified. Vasopressin gene mutation is responsible for hereditary central diabetes insipidus. Mutant vasopressin precursors have been reported to impair the secretion of wild-type proteins or cause cellular toxicity. Despite the intact production and secretion of vasopressin, the kidney is unable to concentrate urine in nephrogenic diabetes insipidus (NDI). Most congenital NDI patients have mutations in the G protein-coupled vasopressin V2 receptor gene. V2 receptor mutants are shown not to reach the plasma membrane, not to bind AVP, and not to trigger an intracellular cyclic adenosine-monophosphate signal. Congenital NDI with an autosomal recessive inheritance has mutations of Aquaporin-2 gene, a vasopressin-sensitive water channel in the renal inner medullary collecting duct (IMCD). Aquaporin-2 mutant proteins cannot be expressed at the luminal membrane. The corticopapillary osmotic gradient is necessary for renal sensitivity to vasopressin. The vasopressin-regulated urea transporter in IMCD and the chloride channel (CLC-K1) in the ascending loop of the Henle contribute to the formation of the osmotic gradient. NDI has been shown in mice lacking the CLC-K1. The pathophysiological significance of urea transporter and CLC-K1 has yet to be demonstrated in patients with NDI.

Regulation of vascular endothelial growth factor production and angiogenesis by the cytoplasmic tail of tissue factor

Tissue factor (TF), a transmembrane receptor for coagulation factor VII/VIIa, is aberrantly expressed in human cancers. We demonstrated a significant correlation between TF and vascular endothelial growth factor (VEGF) production in 13 human malignant melanoma cell lines (r(2) = 0.869, P < 0.0001). Two of these cell lines, RPMI-7951, a high TF and VEGF producer, and WM-115, a low TF and VEGF producer, were grown s.c. in severe combined immunodeficient mice. The high-producer cell line generated solid tumors characterized by intense vascularity, whereas the low producer generated relatively avascular tumors, as determined by immunohistologic staining of tumor vascular endothelial cells with anti-von Willebrand factor antibody. To investigate the structure-function relationship of TF and VEGF, a low-producer melanoma cell line (HT144) was transfected with a TF cDNA containing the full-length sequence, a cytoplasmic deletion mutant lacking the coding sequence for the distal three serine residues (potential substrates for protein kinase C), or an extracellular domain mutant, which has markedly diminished function for activation of factor X. Cells transfected with the full-length sequence produced increased levels of both TF and VEGF. Transfectants with the full-length sequence and the extracellular domain mutant produced approximately equal levels of VEGF mRNA. However, cells transfected with the cytoplasmic deletion mutant construct produced increased levels of TF, but little or no VEGF. Thus, the cytoplasmic tail of TF plays a role in the regulation of VEGF expression in some tumor cells.

A novel apoptotic cascade mediated by CDK4 in rat pheochromocytoma PC12 cells

Apoptosis induced by serum withdrawal in pheochromocytoma PC12 cells is promoted by overexpression of cyclin-dependent kinase 4 (CDK4). We compared CDK4-promoted apoptosis with that induced by serum withdrawal alone in PC12 cells. Protein synthesis inhibitors did not prevent apoptosis in parental cells, but prevented the promotion of apoptosis by CDK4 overexpression. Nerve growth factor, basic-fibroblast growth factor, and Bcl-2 proteins protected both parental and CDK4-overexpressing cells from apoptosis. However, insulin-like growth factor-I and Bcl-X(L) protein only partially inhibited apoptosis in the CDK4-overexpressing cells. Bcl-2 or Bcl-X(L) had no significant effect on CDK4 kinase activity in both cell lines. These results suggest a novel CDK4-mediated apoptotic cascade which is normally restrained, but which is activated by CDK4 overexpression. This apoptotic cascade should eventually converge with the cascade induced by serum withdrawal in normal PC12 cells. We discuss the interactions among these apoptotic cascades and the points where anti-apoptotic agents act.

Deletion and nonsense mutations of the connexin 32 gene associated with Charcot-Marie-Tooth disease

Two patients with a mild to moderate phenotype of Charcot-Marie-Tooth disease were identified to carry the mutations of the connexin (Cx) 32 gene. One of the patient had a novel nonsense mutation of tryptophan at amino acid 132 and the other had a deletion of the Cx 32 gene. Our study indicated that a loss of Cx 32 function contributes to a major pathogenesis of X-linked Charcot-Marie-Tooth disease.

Rectal cancer in a 13-year-old boy without a detectable germline mutation in FAP and HNPCC genes

Hereditary non-polyposis colorectal cancer (HNPCC) is characterized by familial clustering and early onset. It is unclear, however, whether the early onset of colorectal cancer necessarily represents HNPCC. A 13-year-old patient had rectal cancer and underwent curative surgery. DNA from this patient was examined for replication errors (RER) and genes related to familial colorectal cancer (APC, hMSH2, and hMLH1). The patient had a negative family history of colorectal cancer, did not show the RER phenotype, and had no germline mutation of the APC, hMSH2, and hMLH1 genes. The present case suggests that an unusually young patient with colorectal cancer is not always an HNPCC proband. Observation over time, however, will be needed, as a first mutator of familial colorectal cancer could be missed.

Apolipoprotein E4 accelerates dementia and increases cerebrospinal fluid tau levels in Alzheimer's disease

To examine the effect of apolipoprotein E (ApoE) 4 on the progression of Alzheimer's disease (AD), the clinical course of 33 AD patients (17 cases with ApoE epsilon4 and 16 cases without ApoE epsilon4) was evaluated with the mini-mental state examination (MMSE) and cerebrospinal fluid (CSF) biological markers. The decline of MMSE scores to zero was shortened in the ApoE4 group. During a mean follow-up of 20 months, a significant increase of CSF tau levels was observed in the ApoE4 group. A lower level of CSF A beta1-42(43) was found in both the ApoE4 and non-ApoE4 groups than in age-matched normal controls. The ApoE epsilon4 allele accelerates the progression of dementia and increases the levels of CSF tau in AD patients.

Lipoprotein-free amyloidogenic peptides in plasma are elevated in patients with sporadic Alzheimer's disease and Down's syndrome

About 90% of the soluble amyloid beta (sA beta) that circulates in normal human plasma is associated with lipoprotein particles. In sporadic Alzheimer's disease patients, free sA beta42 but not sA beta40 is increased approximately 2.3-fold compared with age-matched controls, although a more marked elevation (approximately 8-fold for free sA beta40 and about 20-fold for sA beta42) is found in Down's syndrome patients. The data suggest that lipoprotein-sA beta dissociation may contribute to the influx of sA beta into the brain as a result of decreased plasma clearance.

Analysis of aldehyde dehydrogenase 2 gene polymorphism and ethanol patch test as a screening method for alcohol sensitivity

To assess clinical availability of the aldehyde dehydrogenase (ALDH) 2 gene polymorphism to detect alcohol sensitivity among a Japanese population, we determined the ALDH 2 genotypes and also compared to an ethanol patch test in 119 young Japanese. Their alcohol sensitivity was evaluated by a questionnaire on the frequency of alcohol-associated symptoms when they drink. Genomic DNA was extracted from blood samples and amplified by polymerase chain reaction (PCR). PCR primers were flanking the polymorphic region in exon 12 of the ALDH 2 gene. The distribution of the typical homozygote, the heterozygote and the atypical homozygote was 63.9, 31.9 and 4.2%, respectively. Gene frequencies of the typical and atypical alleles calculated from the genotype frequencies were 0.80 and 0.20. The atypical genotypic homozygotes were positively associated with facial flushing symptom, but not with positive response for ethanol patch test. These results indicate that ALDH 2 genotypes determination is essential to detect alcohol sensitivity whereas the ethanol patch test has some limitations.

Effects of AH-1058, a new antiarrhythmic drug, on experimental arrhythmias and cardiac membrane currents

AH-1058 is a newly synthesized antiarrhythmic agent. We investigated the antiarrhythmic and electrophysiological effects of AH-1058 in experimental arrhythmia models and isolated cardiomyocytes. In the ouabain-induced arrhythmia model of the guinea pig, pretreatment with AH-1058 (0.1-0.3 mg/kg, i.v.) delayed the appearance of premature ventricular complex (PVC) and ventricular fibrillation (VF) induced by intravenous infusion of ouabain. However, disopyramide (10 mg/kg, i.v.) delayed only that of PVC, and verapamil (1 mg/kg, i.v.) failed to affect the ouabain-induced ventricular arrhythmias. In the reperfusion-induced arrhythmia model of the rat, in which 5-min coronary occlusion and 10-min reperfusion were produced, AH-1058 (0.1-0.3 mg/kg, i.v.) inhibited the incidence of both ventricular tachycardia (VT) and VF, whereas disopyramide (5 mg/kg, i.v.) inhibited only reperfusion-induced VF. On the other hand, a higher dose of AH-1058 (1 mg/kg, i.v.) did not affect the aconitine-induced arrhythmias in rats, which were inhibited by disopyramide (5 mg/kg, i.v.). We also confirmed oral activity of AH-1058 in the reperfusion-induced arrhythmia model of the rat. AH-1058, at doses of 2-4 mg/kg, dose-dependently inhibited VT and VF. Electrophysiological experiments with patch-clamp techniques revealed that AH-1058 potently suppressed the L-type Ca2+ currents in isolated cardiomyocytes of the guinea pig. These results suggest that AH-1058 is a potent antiarrhythmic drug having a Ca2+ channel-blocking action. The antiarrhythmic profile of AH-1058 is different from that of disopyramide and verapamil.

Carboxyl-terminal fragments of presenilin-1 are closely related to cytoskeletal abnormalities in Alzheimer's brains

To clarify the role of presenilin-1 (PS-1) in the pathology of Alzheimer's disease (AD), we tested four antisera to PS-1. The specific antisera to the N-terminus (HSN-2) and C-terminus (HS-C) of PS-1 detected a 44/40kD holoprotein, a 25kD N-terminal fragment (NTF) and a 16kD C-terminal fragment (CTF) of PS-1 in COS-7 cells. The 25kD NTF and 16kD CTF were observed in human brains, and their amounts were not significantly different between the control and AD brains. The antibody HS-C labeled extensive neurofibrillary tangles, dystrophic neurites and curly fibers in the AD brains. In the paired helical filament (PHF) fraction containing A68 protein from AD brains, a smear pattern of CTFs was revealed. Antisera (HS-L292 and HS-L300) to cleavage sites of PS-1 also revealed immunoreactive neurofibrillary tangles in the AD brain sections and the smear pattern of CTFs of A68 protein fraction. The CTFs of PS-1 accumulate with PHF tau, suggesting a close relationship between PS-1 and cytoskeletal abnormalities in AD brains.

Glucocorticoidal regulation of pituitary vasopressin content in rats

Although glucocorticoids are known to attenuate vasopressin (AVP) secretion, it is still controversial whether glucocorticoids act on the hypothalamo-neurohypophysial system. We report here glucocorticoidal regulation of pituitary AVP content, which is a specific indicator for the system. The hypothalamic AVP mRNA content and the pituitary AVP content were measured in rats given dexamethasone (2 mg/kg, 2 times over the course of 5 d) or the glucocorticoid receptor antagonist RU-38486 (20 mg/kg, 3 times over the course of 3 d) during euhydration or dehydration. In dexamethasone-treated rats, both the hypothalamic AVP mRNA content and pituitary AVP content decreased after dehydration. In contrast, in the RU-38486 group the hypothalamic AVP mRNA content and pituitary AVP content increased in both euhydrated and dehydrated rats. These results suggest that glucocorticoids may act on hypothalamo-neurohypophysial vasopressinergic system and attenuate its activity under both basal and dehydrated states.

Tumor extension and cell proliferation in adenocarcinomas of the lung

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

Analysis of spinocerebellar ataxia type 2 gene and haplotype analysis: (CCG)1-2 polymorphism and contribution to founder effect

Spinocerebellar ataxia type 2 is a familial spinocerebellar ataxia with autosomal dominant inheritance. The gene responsible was recently cloned and this disorder was found to be the result of a CAG expansion in its open reading frame. We analysed 13 SCA2 patients in seven unrelated families in Gunma Prefecture, Japan. In four of the seven families, we detected CCG or CCGCCG interruptions in only the expanded alleles. Cosegregation of these polymorphisms with SCA2 patients was established within each family. Together with the results of haplotype analyses, we considered that at least two founders were present in our area and that these (CCG)1-2 polymorphisms may make analysis of founder effects easier. By sequencing analysis we found that although the number of the long CAG repeat varied in each subclone of expanded alleles, these polymorphisms did not change their configuration. This finding suggests that CCG or CCGCCG sequences are stable when surrounded by the long CAG repeat and a single CAG. Moreover, the presence of these polymorphisms may lead to miscounting the repeat size by conventional estimation using a size marker such as an M13 sequencing ladder. Therefore we should consider these polymorphisms and accurately determine the repeat size by sequencing.

A comparison of tau protein in cerebrospinal fluid between corticobasal degeneration and progressive supranuclear palsy

Many clinical and pathological discussions have been focused on the difficulty of differential diagnosis between corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP) in recent years. This study was conducted to evaluate the usefulness of tau proteins in cerebrospinal fluid (CSF) for the differentiation of these two diseases. Subjects consisted of 10 patients with CBD (four males and six females with a mean age of 67.9+/-5.8 years), 12 patients with PSP (eight males and four females with a mean age of 62.6+/-5.8 years) and 36 control subjects (CTL) (16 males and 20 females with a mean age of 65.8+/-9.9 years). The CBD group included patients with probable CBD, while all the patients in the PSP group satisfied the diagnostic criteria developed by the National Institute of Neurological Disorders and Stroke and Society for PSP (NINDS-SPSP). CSF tau proteins were measured with the sandwich ELISA method (Innogenetics, Belgium). The CSF tau protein level was 320.1+/-86.5 pg/ml in the CBD group, 151.5+/-52.7 pg/ml in the PSP group and 128.7+/-91.7 pg/ml in the CTL group. Significant differences were noted in tau protein levels between the CBD group and both the PSP group (P<0.001) and the CTL group (P<0.005). We suggested that the measurement of CSF tau proteins may be useful for the differentiation between CBD and PSP.

CDK4, a possible critical regulator of apoptosis in rat pheochromocytoma PC12 cells

The function of cell cycle regulator molecules during apoptosis induced by serum withdrawal was examined in rat pheochromocytoma PC12 cells. When human cDNAs encoding cyclins, cyclin-dependent kinase 2 (CDK2), CDK4, and cell-division cycle 2 (CDC2), were introduced, only CDK4-overexpressing cells were more prone to apoptosis compared with parental cells. In the parental cells, serum withdrawal resulted in the upregulation of CDK4 protein expression 6.6-fold for the first 12 h after serum withdrawal. In contrast, CDK4 protein levels in CDK4-overexpressing cells remained constant for the first 12 h followed by a gradual decline. Expression of cyclin D1 was upregulated in both cell lines. The change in CDK4 kinase activity almost paralleled that of CDK4 protein expression. These results suggest that CDK4 kinase activity is one of the critical regulators in the apoptotic cascade in PC12 cells.

Mutagenicities of 2,4- and 2,6-dinitrotoluenes and their reduced products in Salmonella typhimurium nitroreductase- and O-acetyltransferase-overproducing Ames test strains

Mutagenicities of 2,4- and 2,6-dinitrotoluene (2,4-and 2,6-DNT), and reduced metabolites formed by the incubation of 2,4- and 2,6-DNT with Salmonella typhimurium TA98, were tested using S. typhimurium YG strains possessing high level of nitroreductase (NR) and/or O-acetyltransferase (OAT) activities. All compounds tested showed greatest mutagenic activities toward strains YG1041 and YG1042, which possess high levels of NR and OAT activities. The relative mutagenic activities of 2,4-DNT and its related compounds toward YG1041 and YG1042 were aminonitrotoluenes<2,4-DNT<2,2'-dimethyl-5, 5'-dinitroazoxybenzene (2,2'-DM-5, 5'-DNAOB)4-hydroxylamino-2-nitrotoluene (4HA2NT)<<4, 4'-dimethyl-3,3'-dinitroazoxybenzene (4,4'-DM-3,3'-DNAOB), and aminonitrotoluenes (2A4AT, 4A2NT)<2,4-DNT<4HA2NT4,4'-dimethyl-3, 3'-dinitroazoxybenzene (4,4'-DM-3,3'-DNAOB)<2HA4NT, respectively. In addition, the relative mutagenic activities of 2,6-DNT and its related compounds toward YG1041 and YG1042 were 2, 6-DNT<2-hydroxylamino-6-nitrotoluene (2HA6NT)<2,2'-dimethyl-3, 3'-dinitroazoxybenzene (2,2'-DM-3,3'-DNAOB), and 2-amino-6-nitrotoluene (2A6NT)<2,6-DNT<2HA6NT, respectively. These results, together with previous findings, suggested that aminohydroxylamino dimethylazoxybenzenes or aminohydroxylamino dimethylazobenzenes produced either by the reduction of hydroxylaminonitrotoluenes or by the reduction of dimethyl dinitroazoxybenzenes are active metabolites responsible for the mutagenic activities of 2,4- and 2,6-DNT.

[Endothelial nitric oxide synthase gene polymorphism and hypertension]

Nitric oxide (NO) is produced by endothelial cells and serves as a potent vasodilator. Several lines of evidence have shown that NO plays an important role in the regulation of blood pressure and regional blood flow. Endothelial NO synthase (eNOS) gene polymorphisms exhibit a positive association in myocardial infarction and smoking-dependent risk of coronary artery disease. However, the relationship between eNOS gene polymorphisms and hypertension is controversial. To examine the possible involvement of the eNOS gene in the genetic basis for hypertension, we identified genotypes for 2 eNOS gene polymorphisms in 166 hypertensive and 174 normotensive populations in Aomori prefecture, in northern Japan. The specific genotypes for Glu298Asp missense variant and variable numbers of tandem repeats in intron 4 (eNOS 4b/4a) were isolated using allele specific gene amplification and restriction fragment length polymorphism. The 298Asp variant was significantly correlated to hypertension in these groups (odds ratio, 1.8; 95% confidence interval, 1.1-3.2). The allelic frequencies of 298Asp for Glu298 in hypertensive patients were significantly higher than those in normotensive subjects (0.136 vs 0.083, p < 0.05). However, disequilibrium of eNOS4b/4a was absent between these 2 groups. These results suggest that Glu298Asp is a genetic susceptibility factor for hypertension.

Molecular analysis of a de novo mutation for spinocerebellar ataxia type 6 and (CAG)n repeat units in normal elder controls

Spinocerebellar ataxia type 6 (SCA6) is an autosomal dominant spinocerebellar degenerative disease caused by CAG repeat expansions in the human alpha1A voltage-dependent calcium channel subunit gene (CACNL1A4). We analyzed 15 SCA6 patients in 14 unrelated Japanese families and 52 healthy Japanese aged over 74 years. Sequence analysis was performed to determine the correct number of CAG repeats. The expanded CAG repeat number was 23.6+/-2.1 (mean+/-S.D., n=15) with a range of 20-29, and the shortest expanded allele was 20 repeats. Moreover, the analysis of normal subjects revealed that the CAG repeat number of normal alleles was 12.3+/-1.9 (n=104) with a range of 7-18. We concluded that the normal range of CAG repeats in the CACNL1A4 gene is 18 or less, and that the disease range is 20 or more. Of 15 SCA6 patients, three sporadic cases were observed. In one male patient with 26 CAG repeats, the CAG repeat numbers of his parents were within normal range. His expanded allele was considered to be caused by an expansion of a normal allele from his mother (14 or 17 repeats). This is the first SCA6 case which was genetically proven to occur due to a de novo mechanism, suggesting that larger CAG repeats of normal alleles in the CACNL1A4 gene may be unstable and result in full expansion.

Active cyclin A-CDK2 complex, a possible critical factor for cell proliferation in human primary lung carcinomas

Expression of cyclins A and E and cyclin-dependent kinase 2 (CDK2) was examined immunohistochemically in 190 cases of human lung carcinoma. Cyclin A and CDK2 were expressed in the majority of squamous cell carcinomas, small cell carcinomas, and large cell carcinomas, but in significantly fewer cases of adenocarcinomas. Cyclin E was expressed in a minority of all subtypes. In particular, well differentiated cells in squamous cell carcinoma stained positively for cyclin E; in contrast, cyclin A was expressed in the nonkeratinized proliferating areas of the tumor nests. Immunoblotting revealed that all these proteins were expressed at higher levels in tumor tissues than in adjacent normal tissues. Immunoprecipitation also revealed higher levels of cyclin A and cyclin E associated with CDK2 in tumor tissues. Furthermore, tumor tissues which exhibited higher cyclin A and CDK2 expression also had higher CDK2 kinase activity. However, cyclin E-associated kinase activity was barely detectable even in tumor samples exhibiting higher cyclin E expression. Consistent with these data, elevated expression of cyclin A correlated to shorter survival periods in contrast to expression of cyclin E, which correlated to longer survival periods. These results suggest that in human lung carcinomas, elevated expression of active cyclin A-CDK2 complexes with associated higher CDK2 kinase activity is critical for promoting cell cycle progression and unrestrained proliferation of tumor cells and can be a predictive marker for patients' prognosis. On the other hand, immunohistochemical detection of cyclin E-CDK2 reflects accumulation of inactive forms of protein complexes, implying differentiation or senescence of the tumor and the better prognosis.

Familial spinocerebellar ataxia with cerebellar atrophy, peripheral neuropathy, and elevated level of serum creatine kinase, gamma-globulin, and alpha-fetoprotein

Here, we report a familial spinocerebellar ataxia (FSCA), which has clinical features similar to Friedreich's ataxia, an ataxia with isolated vitamin E deficiency, and ataxia telangiectasia. However, the serum levels of creatine kinase, gamma-globulin, and alpha-fetoprotein were elevated, and biochemical and genetic analyses ruled out diagnosis of these three ataxias as well as other FSCAs. Thus, this family is thought to have a new type of FSCA.

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.

A Japanese family with adrenoleukodystrophy with a codon 291 deletion: a clinical, biochemical, pathological, and genetic report

We report a Japanese family with adrenoleukodystrophy (ALD) with a three base pair deletion (delGAG 291) in the ALD gene. A variety of phenotypes were observed within this family. While the proband (patient 1) was classified as having a rare intermediate type of adult cerebral and cerebello-brain stem forms, his younger brother (patient 2) and nephew (patient 3) had a childhood ALD type. Another nephew (patient 4) of patient 1 was classified as having an adolescent form. The tau level in the cerebrospinal fluid (CSF) in patient 1 was as high as that of patients with Alzheimer's disease (AD). His brain magnetic resonance image (MRI) showed abnormalities in the bilateral cerebellar hemispheres and brain stem, but not in the cerebral white matter, where marked reductions of the cerebral blood flow and oxygen metabolism were clearly demonstrated by positron emission tomography (PET). In patients 2 and 3, the autopsy findings showed massive demyelination of the cerebral white matter with sparing of the U-fibers, compatible with the findings of childhood ALD. Oleic and erucic acids (Lorenzo's Oil) were administered to patients 1 and 4, but sufficient effectiveness was not obtained. The findings in this family suggest that delGAG291 is part of the cause of Japanese ALD with phenotypic variations. Moreover, although the scale of the study is limited, there is a possibility that PET can detect an insidious lesion which is undetectable by computed tomogram (CT) or MRI analysis, and that the higher level of tau reflects the process of neuronal degeneration in ALD. Lorenzo's Oil should be given in the early stage.

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.

Effects of endothelin-induced nitric oxide on venous circulation and renal water-electrolyte handling

To assess the interaction of endothelin (ET) with nitric oxide (NO) and the effects on venous circulation and handling of renal water and electrolytes, ET (1.0 ng/kg/min) or saline was administered with or without three doses (0.27, 2.7 and 27 ng/kg/min for 40 min) of N omega-nitro-L-arginine methyl ester (L-NAME), and NO synthase inhibitor, in anesthetized dogs. ET increased total peripheral resistance (TPR), pulmonary capillary wedge pressure (PCWP), urine flow (UF), and urinary K excretion (UKV), and decreased cardiac output (CO), urinary osmolality (Uosm), renal plasma flow (RPF), and glomerular filtration rate (GFR). L-NAME increased blood pressure (BP), TPR, PCWP, right atrial pressure (RAP), and mean circulatory filling pressure (MCFP), and decreased CO, RPF, and GFR, ET plus L-NAME markedly increased TPR, resistance to venous return, and plasma atrial natriuretic peptide (ANP), but not BP and MCFP, and curtailed the ET-induced responses in UF, UKV, and Uosm. Plasma aldosterone (ALD) was decreased in all groups, but plasma vasopressin (AVP) and renin activity (PRA) were not altered in any group. These results indicate that ET-induced NO formation might mitigate increases in venous as well as arterial vascular resistance and changes in renal handling of water and electrolytes, and might also play an inhibitory role in ANP release but not in PRA or AVP and ALD release.

Large cell neuroendocrine carcinoma of the lung: a histologic and immunohistochemical study of 22 cases

Large cell neuroendocrine carcinoma (LCNEC) of the lung is defined as a poorly differentiated and high-grade neuroendocrine tumor that is morphologically and biologically between atypical carcinoid and small cell lung carcinoma (SCLC). During a survey concerning bcl-2 protein expression in the subtypes of lung cancer, we noticed that two previously diagnosed non-SCLCs met the criteria for LCNEC. Because LCNEC is a newly recognized clinicopathologic entity and because all reported cases have been retrieved from the so-called "neuroendocrine tumor file," we suspected that LCNEC had been underdiagnosed. In the present study, we histologically reviewed 766 surgically resected lung cancers and were able to diagnose 22 (2.87%) LCNECs with the neuroendocrine features subsequently confirmed by immunostaining for multiple neuroendocrine markers. Each case stained positively for at least three general neuroendocrine markers, and 12 (54.5%) also were positive for neuroendocrine hormones. Histologically, most LCNECs showed a marked decrease in or a loss of organoid architecture and could be mistaken for poorly differentiated adenocarcinoma or squamous cell carcinoma. Because our LCNECs are the first to be identified by retrospective review of routinely diagnosed lung cancers, and 18 had been classified as non-SCLC, they may represent cases relatively difficult to diagnose. The present study shows that the most difficult diagnostic factor of LCNEC is the recognition of its light microscopic neuroendocrine features, and LCNEC must be distinguished not only from atypical carcinoid or SCLC, but also from common non-SCLC. Histologically, when an organoid architecture is subtle or absent, the rosettelike structure becomes the best marker for the recognition of neuroendocrine differentiation. Clinically, the prognosis for our LCNECs was significantly worse than that for stage-comparable non-SCLCs (p = 0.046).

Analysis of spinocerebellar ataxia type 2 in Gunma Prefecture in Japan: CAG trinucleotide expansion and clinical characteristics

We analyzed 13 patients with spinocerebellar ataxia type 2 (SCA2) in seven unrelated families who live in Gunma Prefecture, Japan (population approx. 2,000,000), and documented the clinical and molecular properties correlated with the CAG repeat expansion. Twelve of the 13 patients and one presymptomatic female were genetically examined, and the CAG repeat number of the expanded and normal alleles was 40.8+/-4.8 (mean+/-S.D., n=13) and 22+/-0 (n=13), respectively. The repeat size of the expanded alleles was inversely correlated with the patients' age at onset. Paternal anticipation was observed, accompanied by an increase of the CAG repeat size. The patients presented here were clinically characterized by a relatively higher frequency of slow saccades, hyporeflexia, hypotonia, and tremor. A number of peaks in the expanded allele on polyacrylamide gel electrophoresis showed the presence of cell mosaicism in SCA2 as well. In Gunma Prefecture, SCA2, Machado-Joseph disease and spinocerebellar ataxia type 6 are almost equally present and at higher frequencies than spinocerebellar ataxia type 1 and hereditary dentatorubropallidoluysian atrophy, which are rare. Thus, the difference of frequency of autosomal dominant spinocerebellar ataxias may be present in Japan.

Expression of HuD protein is essential for initial phase of neuronal differentiation in rat pheochromocytoma PC12 cells

HuD is a neuronal-specific, RNA-binding protein. Here we examined the change in the expression of HuD protein during nerve growth factor-mediated differentiation of PC12 cells. As cells differentiated and extended neurites, expression of HuD gradually increased up to 1.5-fold. When HuD expression was counteracted by antisense oligonucleotide, neurite extension was completely inhibited, yet the morphology of differentiated cells remained unchanged even after that treatment. Furthermore, this morphological change correlated well with the downregulation of cyclin-dependent kinase 2 activity. These results suggest that the HuD is critically involved in the initial phase of neuronal differentiation.

Activation of coagulation and angiogenesis in cancer: immunohistochemical localization in situ of clotting proteins and vascular endothelial growth factor in human cancer

Thrombin-catalyzed, cross-linked fibrin (XLF) formation is a characteristic histopathological finding in many human and experimental tumors and is thought to be of importance in the local host defense response. Although the pathogenesis of tumor-associated fibrin deposition is not entirely clear, several tumor procoagulants have been described as likely primary stimuli for the generation of thrombin (and XLF) in the tumor microenvironment (TME). In a previous study of a variety of human tumors we have shown that tissue factor (TF) is the major procoagulant. However, the relative contribution to fibrin deposition in the TME of tumor cell TF and host cell TF (eg, macrophage-derived) was not established. In addition, recent evidence has implicated TF in the regulation of the synthesis of the pro-angiogenic factor vascular endothelial growth factor (VEGF) by tumor cells. In the current study we used in situ techniques to determine the cellular localization of XLF, TF, VEGF, and an alternative tumor procoagulant, so-called cancer procoagulant (CP), a cysteine protease that activates clotting factor X. In lung cancer we have found XLF localized predominantly to the surface of tumor-associated macrophages, as well as to some endothelial cells and perivascular fibroblasts in the stromal area of the tumors co-distributed with TF at the interface of the tumor and host cells. Cancer pro-coagulant was localized to tumor cells in several cases but not in conjunction with the deposition of XLF. TF and VEGF were co-localized in both lung cancer and breast cancer cells by in situ hybridization and immunohistochemical staining. Furthermore, a strong relationship was found between the synthesis of TF and VEGF levels in human breast cancer cell lines (r2 = 0.84; P < 0.0001). Taken together, these data are consistent with a highly complex interaction between tumor cells, macrophages, and endothelial cells in the TME leading to fibrin formation and tumor angiogenesis.