Acetylated histone H4 is reduced in human gastric adenomas and carcinomas

Acetylation of core histones is closely linked to transcriptional activation of various genes. The acetylation levels of nucleosomal histones can be modified through a balance of histone acetyltransferases and deacetylases. To elucidate the role of histone acetylation in human gastric carcinogenesis, we studied the status of histone H4 acetylation in gastric carcinoma tissues and corresponding non-neoplastic mucosa. The status of histone acetylation was assessed by examining the expression of acetylated histone H4 through Western blotting and immunohistochemistry using an anti-acetylated histone H4 antibody. The levels of acetylated histone H4 expression were obviously reduced in 72% (13/18) of gastric carcinomas in comparison with non-neoplastic mucosa by Western blotting. In immunohistochemistry, acetylated histone H4 was clearly detected in the nuclei of both non-neoplastic epithelial and stromal cells, whereas the levels of acetylated histone H4 were heterogeneous or reduced in 66% (38/57) of gastric carcinomas and 46% (6/13) of gastric adenomas. Reduced expression of acetylated histone H4 was also observed in some areas of intestinal metaplasia adjacent to carcinomas. Reduction in the expression of acetylated histone H4 was significantly correlated with advanced stage, depth of tumor invasion and lymph node metastasis. These results suggest that low levels of histone acetylation may be closely associated with the development and progression of gastric carcinomas, possibly through alteration of gene expression.

Promoter methylation status of the DNA repair genes hMLH1 and MGMT in gastric carcinoma and metaplastic mucosa

Hypermethylation of CpG islands in the promoter region is associated with the silencing of a variety of tumor suppressor genes. DNA repair genes human Mut L homologue 1 (hMLH1) and O(6)-methylguanine-DNA methyltransferase (MGMT) have been shown to be hypermethylated in certain carcinomas. We studied DNA methylation of CpG islands in hMLH1 and MGMT in 50 gastric carcinomas and 10 intestinal metaplastic mucosa samples. We analyzed the methylation status of hMLH1 and MGMT using methylation-specific polymerase chain reaction and DNA sequencing analysis. We measured protein levels of hMLH1 using Western blot and immunohistochemical analysis. CpG island hypermethylation of hMLH1 and MGMT was detected in 11 (22%) and 8 (16%) of the 50 gastric tumors, respectively. Hypermethylation of the promoter was more common in intestinal-type gastric carcinomas than in poorly diffuse-type gastric carcinomas (p = 0.016 and 0.021, respectively; Fisher's exact test). However, hMLH1 promoter hypermethylation did not coincide with MGMT promoter hypermethylation except in 1 patient. Hypermethylation of the hMLH1 promoter but not the MGMT promoter occurred in intestinal metaplastic mucosae. Immunohistochemical analysis revealed a corresponding reduction in hMLH1 protein expression in some of the intestinal metaplastic mucosae. Our results suggest that at least two types of promoter methylation participate in the development of gastric carcinoma. Tumor-specific promoter hypermethylation of hMLH1 may be an early event in carcinogenesis in the stomach.

Different accumulations of 3-ketoacyl-CoA thiolase precursor in peroxisomes of Chinese hamster ovary cells harboring a dysfunction in the PEX2 protein

The peroxisomal localization of 3-ketoacyl-CoA thiolase (hereafter referred to as thiolase) was characterized in five Chinese hamster ovary (CHO) mutant cell lines each harboring a dysfunction in the PEX2 protein. PT54 (Pex2pN100) cells carry a nonsense mutation that results in the PEX2 protein truncated at amino acid position 100. SK24 (Pex2pC258Y) cells carry a missense mutation resulting in the amino acid substitution of a cysteine residue by a tyrosine residue at amino acid position 258 of the PEX2 protein. The WSK24 (Pex2pC258Y/+wild) cell line is a stable transformant of SK24 (Pex2pC258Y) cells transfected with wild-type rat PEX2 cDNA. The SPT54 (Pex2pN100/+Pex2pC258Y) and WPT54 (Pex2pN100/+wild) cell lines are stable transformants of PT54 (Pex2pN100) cells transfected with the mutant PEX2 cDNA from SK24 (Pex2pC258Y) cells and wild-type rat PEX2 cDNA, respectively. In these cell lines, except PT54 (Pex2pN100), thiolase appeared to be localized in peroxisomes, as it is in the wild-type cells. When the molecular size of the enzyme was examined on SDS-polyacrylamide gel electrophoresis, the peroxisome-localized enzyme exhibited a larger precursor form in these mutant cells. The characterizations with salt wash, sodium carbonate extraction and proteinase K digestion indicated that the precursor forms of the enzyme were accumulated at different states in peroxisomes of these mutant cells. The dispositions on the peroxisomal membrane were further sustained by differential permeabilization using digitonin, followed by immunocytochemical fluorescence. These results suggest that PEX2 protein functions differently on two processes of the maturation and the disposition in the import pathway of thiolase.

Molecular diagnosis of gastric cancer: present and future

Although histopathological diagnosis is extremely useful for the definitive as well as the supportive diagnosis of gastric cancer in clinical practice, it is limited in certain respects. Over the past 15 years, integrated research in molecular pathology has clarified the details of genetic and epigenetic abnormalities of cancer-related genes in the course of the development and progression of gastric cancer. These abnormalities, which include telomerase activation, genetic instability, and abnormalities in oncogenes, tumor suppressor genes, cell-cycle regulators, cell adhesion molecules, and DNA repair genes, could be effective markers in the molecular diagnosis of gastric cancer. It is possible that the molecular analysis of these alterations in histopathology specimens may overcome deficiencies in diagnoses that depend only on histomorphology, and, consequently, we may be able to improve the differential diagnosis of cancer, obtain information on the grade of malignancy, and identify patients at high risk of developing multiple primary cancers. In Hiroshima, we have established a system of molecular-pathological diagnosis as a routine service; about 5,000 lesions of the stomach have been subjected to this diagnosis, and much useful information has been obtained. In the near future, genetic analysis by means of DNA microarray may become routine in the diagnosis of gastric cancer. Genetic analysis of histopathology specimens may make clear the characteristics of individual cancers; indicating the common and specific features of molecular pathogenesis that may be directly connected with gene therapy or molecular-targeted therapy. By analyzing the relationship between single-nucleotide polymorphisms and cancer susceptibility, we will be able to obtain information on cancer prevention from histopathology samples.

Prospective study of Ki-67 labeling index in the mucosa adjacent to cancer as a marker for colorectal cancer metastasis

Multivariate regression analysis has shown that Ki-67 labeling index in the mucosa adjacent to cancer was the most significant marker for colorectal cancer metastasis among several metastasis-related parameters according to our previous retrospective data base (7). We have performed a prospective study to ascertain whether Ki-67 labeling index in the mucosa adjacent to cancer is a useful preoperative diagnostic marker for colorectal cancer metastasis. In 182 registered cases colonoscopically biopsied, we performed surgical resection of the cancer in 37 adenocarcinoma cases, which were registered in the study. In 31 out of the 37 cases except for 6 cases with an insufficient amount of non-neoplastic mucosa, preoperative diagnosis for metastasis was performed using the Ki-67 cutoff line. The cutoff line was set at 15% according to our previous retrospective database. The preoperative diagnosis for metastasis was compared to the pathological findings of the resected specimen. The incidences of correct diagnosis for metastasis was 81% (25/31). There were 3 false positive cases and 3 false negative cases in Dukes' A-B and Dukes' C, respectively. The mean Ki-67 labeling index in the mucosa adjacent to cancer of Dukes' A-B and Dukes' C-D cases, except for the 6 misdiagnosed cases, was 7.4+/-5.0% and 29.9+9.8%, being significant at p<0.0001 by unpaired Mann-Whitney U test. These results suggest that Ki-67 labeling index in the mucosa adjacent to cancer might be a good marker for metastasis in colorectal cancer.

Frequency of food-dependent, exercise-induced anaphylaxis in Japanese junior-high-school students

BACKGROUND

Food-dependent, exercise-induced anaphylaxis (FEIAn) is classified among the physical allergies. The pathophysiology of FEIAn remains unknown, as does the frequency of FEIAn in the general population.

OBJECTIVE

We sought to study the epidemiology of FEIAn, especially its frequency in junior-high-school students in Yokohama, Japan.

METHODS

A questionnaire asking about the occurrence of FEIAn in school students was sent to all 145 public junior-high-school nurses in Yokohama.

RESULTS

One hundred thirty-two junior-high-school nurses responded to the questionnaire, and 13 (11 boys and 2 girls) cases of FEIAn among 76,229 junior-high-school students were reported. In addition, 24 (12 boys and 12 girls) subjects with exercise-induced anaphylaxis (EIAn) were detected. From this survey, the frequency of FEIAn was 0.017% in this population, and its frequency was significantly higher in boys than in girls (P < .05). The frequency of EIAn was 0.031%, and there was no difference according to sex. Only one third of junior-high-school nurses had any knowledge of FEIAn. We also performed provocation tests in 5 of the 13 cases with FEIAn after obtaining informed consent from the students and their parents and were able to confirm the diagnosis.

CONCLUSION

This study showed that FEIAn and EIAn are relatively rare diseases among junior-high-school students in Yokohama. To avoid serious outcomes, we believe it is important that not only physicians but also school nurses and teachers of physical education be aware of these diseases.

Cortical and subcortical vestibular response to caloric stimulation detected by functional magnetic resonance imaging

The posterior insula, central sulcus, and inferior parietal lobule including the intraparietal sulcus have been considered the vestibular cortex based on functional brain mapping in humans as well as experiments in lower primates. The same regions receive optokinetic, visual, and proprioceptive projections. We examined the cortical and subcortical projection of vestibular activity with visual and proprioceptive input eliminated during caloric stimulation (CS), using functional magnetic resonance imaging (fMRI). Single-shot gradient-echo echoplanar image (EPI) volumes were sensitive to BOLD contrast in oblique orientation. We adopted a pharmacokinetic model for analysis of imaging data from 10 subjects as a group. The insular gyrus, intraparietal sulcus, superior temporal gyrus, hippocampus, cingulate gyrus, and thalamus showed activation by CS. Cortical and subcortical activation during CS in the present study was observed within regions less precisely delineated by other methods. As intraparietal sulcus activation showed right hemispheric dominance, this region may have an oculomotor projection as well as the vestibular input.

Temperature-sensitive phenotype of Chinese hamster ovary cells defective in PEX5 gene

SK32 mutant cells, which were isolated as peroxisome-deficient Chinese hamster ovary (CHO) cells by an advantage of a visible peroxisome form of green fluorescent protein (GFP), were found to suffer from a functional loss of PEX5 gene encoding for PTS1R. The sequence analysis of cDNA indicated that PEX5 gene encoded for the two isoforms composed of 603 amino acids (PTS1RS) and 640 amino acids (PTS1RL). The mutation changed glycine to arginine at amino acid position 343 of PTS1RL (corresponding to the position 306 of PTS1RS) in SK32 cells. The mutant cells exhibited a temperature-sensitive (TS) phenotype on the peroxisomal localizations of the recombinant GFP and urate oxidase appending a genuine peroxisome targeting signal 1 (PTS1), a tripeptide of Ser-Lys-Leu (SKL) at the C-terminus, but did not on that of catalase harboring a divergent PTS1, Lys-Ala-Asn-Leu (KANL) sequence. 3-ketoacyl-CoA thiolase (hereafter referred to as thiolase), which harbors an extension sequence (PTS2) at the N-terminus, never appeared to be affected on the peroxisomal localization in the mutant cells. When thiolase was examined on the molecular size in the mutant cells, the enzyme existed as the larger precursor form in the peroxisomes at 37 degrees C and a considerable part (almost half) was converted to the mature size at 30 degrees C. These results indicate that the amino acid substitution, Gly306Arg in PTS1RS and/or Gly343Arg in PTSRL, gives rise to TS phenotype on the peroxisomal translocation of PTS1 proteins and the maturation of PTS2 protein.

Tentorial enhancement on MR images is a sign of cavernous sinus involvement in patients with sellar tumors

BACKGROUND AND PURPOSE

This study was undertaken to analyze enhancement patterns of the dura around sellar tumors and to compare the results with tumor invasion or compression of the cavernous sinuses. Postoperative enhancement patterns on MR images were compared with preoperative findings.

METHODS

Contrast-enhanced coronal and sagittal MR images were examined prospectively in 96 patients with sellar tumors (65 macroadenomas, 15 microadenomas, 14 Rathke cleft cysts, and two chordomas at the sella). All patients underwent surgical treatment, and pre- and postsurgical features on MR images were compared.

RESULTS

Presurgical MR images showed dural enhancement in 36.5% of the patients: asymmetric tentorial enhancement in 24 patients, symmetric tentorial enhancement in seven, and sphenoidal ridge or clivus enhancement in four. Asymmetric tentorial enhancement disappeared after surgical decompression in seven patients. For evaluation of cavernous sinus invasion ipsilateral to the enhancement, sensitivity and specificity of the asymmetric tentorial enhancement sign were 81.3% and 86.3%, respectively. Sensitivity and specificity of the sign were 42.9% and 93.6% for cavernous sinus involvement, including compression and invasion.

CONCLUSION

Asymmetric tentorial enhancement is a useful sign in the diagnosis of invasion or severe compression of the cavernous sinus by sellar tumor. The sign may represent venous congestion or collateral flow in the tentorium due to obstructed flow in the medial portion of the cavernous sinus.

Promoter hypermethylation of MGMT is associated with protein loss in gastric carcinoma

Aberrant methylation of CpG islands within promoter regions is associated with transcriptional inactivation of various tumor suppressor genes in neoplasms. Recently, O(6)-methylguanine-DNA methyltransferase, MGMT, was shown to be hypermethylated in certain carcinomas, resulting in loss of MGMT protein. We studied DNA methylation of CpG islands of the MGMT gene by methylation specific PCR in 26 gastric carcinoma tissues and 8 gastric carcinoma cell lines for comparison with levels of MGMT protein expression. In addition, we examined p53 mutation status in the same tissues by PCR-SSCP analysis for comparison with MGMT protein expression levels. In total, promoter hypermethylation of the MGMT gene was found in 8 (31%) of the 26 gastric carcinomas with reduced expression of MGMT protein, whereas the hypermethylation was not detected in the 18 carcinomas with non-reduced MGMT expression. MGMT protein expression levels were associated with promoter hypermethylation of MGMT (p = 0.0001; Mann-Whitney test); however, MGMT expression was not associated with p53 mutation status (p = 0.461; Mann-Whitney test). Among in gastric carcinoma cell lines, the TMK-1 cell line showed loss of the MGMT protein association with promoter hypermethylation and this loss was rectified by treatment with a demethylating agent, 5-Aza-2'-deoxycytidine. Our results suggest that transcriptional inactivation of MGMT by aberrant methylation of the promoter region may participate in carcinogenesis in the stomach.

Stereopsis-processing regions in the human parieto-occipital cortex

We performed fMRI on the human parieto-occipital cortex in order to identify the neural processing regions of stereopsis. Visual stimulation for stereopsis was performed with a random-dot stereogram displayed in the image guides of a new binocular visual stimulation device that we developed. Interestingly, regions from the dorsal portion of the occipital lobe to the superior parietal lobule were activated by binocular disparity, while the inferior parietal lobule was not activated. Moreover, these regions were shown as dominant in the right hemisphere. Functional brain mapping revealed that the processing regions of stereopsis were dorsally located in parieto-occipital cortex, and that the superior parietal lobule is an important region for neural processing of human stereopsis.

PTEN expression is maintained in sporadic colorectal tumours

Loss of PTEN (phosphatase and tensin homologue deleted from chromosome 10) function has been implicated in the progression of several types of cancer. Allele loss close to the PTEN locus occurs in sporadic colon cancer and germline PTEN mutations cause Cowden disease, an inherited cancer syndrome characterized by an increased incidence of gastrointestinal tract lesions that can progress to colorectal carcinoma. However, although PTEN is a good candidate for involvement in the pathogenesis of sporadic colon cancer, previous analyses have not revealed a high frequency of somatic mutations in colorectal tumours. Alternative mechanisms which could lead to a loss of PTEN expression in colon cancer have not been investigated. This study monitored PTEN mRNA and protein levels in a panel of 50 tumour tissues obtained from 35 patients with sporadic colon cancer. RT-PCR and immunohistochemistry were used to evaluate the expression of mRNA and protein, respectively, in normal, adenoma and adenocarcinoma colorectal tissues as well as in metastatic lesions. To overcome the problem of heterogeneity and normal stromal cell contamination in homogenized tissue specimens, specific cell types were isolated by microdissection prior to PCR analysis. No loss of PTEN expression was evident in any of the colon tissues examined. PTEN protein was localized exclusively in the cytoplasm of normal and tumour cells and no correlation of immunostaining intensity and tumour stage or grade was revealed. As with previous deletion and mutation analyses, the present study suggests that loss of PTEN expression is not prevalent in sporadic colon cancer.

Isolation of peroxisome-defective CHO mutant cells using green fluorescent protein

The authors constructed a recombinant green fluorescent protein (GFP) (PTS-GFP), which carries peroxisome targeting signal (PTS1 or PTS2) as an additional sequence, by polymerase chain reaction. The gene encoding for the recombinant GFP was constructed into an eukaryotic expression vector, and stable transformant of CHO cell expressing PTS-GFP was isolated, following the transfection of the plasmid encoding for the GFP. Each expressed PTS-GFP appeared to be localized in peroxisomes, because the GFP was observed in cellular structures, as was catalase. The observation proposed a visual screening procedure for isolating peroxisome-defective mutant. Following an enrichment of mutant cells by use of 9-(1'-pyrene)nonanol/ultraviolet irradiation (P9OH/UV) method, five peroxisome-defective mutants were isolated by pursuing the fluorescent signals from GFP. Two mutants (SK24 and SK32) were isolated from CHO cells expressing PTS1-GFP, and three mutants (PT13, PT32, and PT54) were isolated from cells expressing PTS2-GFP. Four mutants, except for PT13, showed cytosolic distributions of both PTS-GFP and catalase. On the other hand, mutant PT13 showed a cytosolic distribution on PTS2-GFP, but a peroxisomal distribution on catalase. Cell fusion analysis between SK24 mutant and other mutants indicated that PT54 mutant is in the same complementation group (CG) as SK24, but that SK32, PT13, and PT32 mutants are in different complementation group(s) from SK24.

Cold suppression of follicle-stimulating hormone activity on proliferation and survival of newt spermatogonia

In newts elevated titers of plasma prolactin (PRL), induced by low temperature, cause apoptosis in the penultimatemitotic stage of spermatogonia, and this cell death is suppressed by antiserum against newt PRL, but only during the initial 3 days of exposure (Yazawa et al., 1999). Thus, factors other than PRL must be involved in spermatogonial death. Follicle-stimulating hormone (FSH) may be a plausible candidate. Accordingly, the current study examined the activityof FSH on the proliferation and survival of spermatogonia at low temperatures in vivo and in vitro. Porcine FSH (pFSH) administration in vivo inhibited spermatogonial death induced at 12 degrees C, but failed to do so at8 degrees C. Also pFSH promoted in vitro the proliferation of spermatogonia at 12 degrees C, but not at 8 degrees C. Furthermore,dibutyryl cyclic AMP stimulated in vitro DNA synthesis of secondary spermatogonia at 12 degrees C, but not at 8 degrees C. These different responses to temperatures were not caused by different levels of mRNA for the receptor of follicle-stimulating hormone, the numberof FSH binding sites, or FSH binding affinity to its receptors in the testicular cells. Thus, the results indicate that a temperature-sensitive period exists duringthe postreceptor process and is responsible for thelack of response of newt testis to FSH at 8 degrees C.

Effects of vitamin B12 on bright light on cognitive and sleep-wake rhythm in Alzheimer-type dementia

The present study investigated the effects of vitamin B12 (VB12) on circadian rhythm in Alzheimer-type dementia (ATD). Twenty-eight ATD patients were treated with bright light therapy (BLT) for 8 weeks. For the latter 4 weeks, half were treated with VB12 with BLT (BLT + VB12). We evaluated the cognitive state with Mini-Mental State Examination and the circadian rhythm with actigraphy after the fourth and eighth week. After the first 4 weeks BLT improved the circadian rhythm disturbances and cognitive state especially in the early stage of ATD. Although the latter 4 week-BLT caused no significant effects on the circadian rhythm; BLT + VB12 improved the vigilance level during the daytime. These results suggest that VB12 has some efficiency to enhance vigilance for ATD patients.

A Utstein-style analysis of prognostic factors related to survival in out-of-hospital cardiac arrests in Akita-City, Japan

To analyze the epidemiology of out-of-hospital cardiac arrests and to elucidate modifiable factors affecting survival, we conducted a prospective cohort study in a middle-sized urban city served by a single emergency medical service (EMS) system in which emergency medical technicians use an automated external defibrillator. Data were collected from out-of-hospital cardiac arrests occurring between 1 January, 1994 and 31 December, 1998 by applying the Utstein style. The main outcome measure was survival at 1 year after hospital discharge. The overall incidence of out-of-hospital cardiac arrest was 71.7/100 000 inhabitants/year. Resuscitations were attempted in 762 of 1118 patients with confirmed cardiac arrest. Of the 762 patients, 37 (4.86%) survived. The cause of cardiac arrest was presumed to be cardiac in 340 (44.6%). Of the 340 cardiac arrests, 180 (52.9%) were witnessed by bystanders. Ventricular fibrillation (VF) was recorded as an initial rhythm in 56 (31.1%) of the 180 patients, and cardiopulmonary resuscitation (CPR) was performed by bystanders in 89 (49.4%). The survival rate was 39.2% (22/56) when cardiac arrest was bystander-witnessed and of cardiac origin with VF as an initial rhythm. VF as an initial rhythm, age of the patients and intervals of call-to-first CPR attempt and collapse-to-arrival at patient's side were major factors relating to survival in the witnessed cardiac arrests of cardiac origin. The age, and gender of the patients, place of collapse and intervals of collapse-to-first CPR and collapse-to-arrival at patient's side were representative factors affecting the incidence of VF as an initial rhythm. The survival rate in Akita-City from bystander-witnessed cardiac arrests of cardiac origin with VF as an initial rhythm was comparable to those in other regions with advanced EMS systems. However, the incidence of VF as an initial rhythm is extremely low. Reduction of intervals of call (collapse)-to-first CPR attempt and collapse-to-arrival at patient's side or authorization of use of automated external defibrillator in basic life support may increase the incidence of VF as an initial rhythm and improve the survival from witnessed cardiac arrests with cardiac origin.

The Ross procedure: Is it the ideal operation for the young with aortic valve disease?

BACKGROUND

Aortic valve prosthesis with adequate hemodynamic performance should allow more complete left ventricular mass regression and normalize left ventricular function. This possibly affects long-term prognosis after aortic valve replacement.

OBJECTIVE

Assessment of hemodynamic performance of pulmonary autograft in the aortic position and the regression of left ventricular mass after the Ross procedure.

METHODS

Between May 1995 and March 1996, 45 patients with mean age of 27.1 years underwent a Ross procedure. Doppler echocardiography and cardiac catheterization were performed on all patients before hospital discharge to evaluate the hemodynamic performance of auto- and homografts, as well as to evaluate left ventricular mass and function. Fourteen patients with follow-up longer than six months were submitted to dobutamine stress echocardiography to study the hemodynamic performance of auto- and homografts during exercise.

RESULTS

Hospital mortality was 6%. After a mean follow-up of 12.8 months (1-23 months) there was one late sudden death. No valve-related event was observed during this period. Immediate and late hemodynamic performance of the pulmonary autografts were normal with an average mean gradient of 1.8 +/- 0.6 mmHg and an average maximum instantaneous gradient of 2.9 +/- 0.9 mmHg. Valvular insufficiency was insignificant. Even during exercise, gradients did not increase significantly with an average mean gradient of 4.3 +/- 2.5 mmHg and an average maximum gradient of 10.4 +/- 6.1 mmHg. Homografts used for right ventricular reconstruction showed excellent immediate hemodynamic performance. However, at late follow-up an increase in flow speed was observed with an average to mean gradient of 10 +/- 7.1 mmHg at rest and 26 +/- 13.2 mmHg during exercise. Left ventricular mass index was normal at rest and during exercise in the majority of patients.

CONCLUSION

Given the normal hemodynamic function of pulmonary autografts, the reduction of ventricular mass and normalization of left ventricular function, in addition to the excellent late follow-up of the patients, the Ross procedure is considered the operation of choice for young patients requiring aortic valve replacement.

Diffusion tensor brain MR imaging in X-linked cerebral adrenoleukodystrophy

Brain diffusion tensor MRI of 11 boys with X-linked adrenoleukodystrophy was performed. The authors determined quantitative isotropic apparent diffusion coefficient (ADC(i)) and fractional anisotropy (FA) values in the white matter. ADC(i) and FA values in the affected white matter were significantly different from those in normal-appearing white matter. Zonal ADC(i) and FA gradations, which might originate from well-established histopathologic zonal changes, existed within affected white matter.

[EEG findings in a case of acute necrotizing encephalopathy of childhood associated with influenza A virus infection]

We reported here a case of symptomatic partial epilepsy following acute necrotizing encephalopathy of childhood associated with influenza A virus infection. This 2-year-old boy underwent repeated EEG recordings, which at the acute stage was dominated by diffuse 1-2 Hz slow waves. The background activity was 5 Hz theta waves on the 49th day. Paroxysmal activities appeared after the 89th day of illness. On the 231st day, EEG showed spike-and-waves on the left and right frontal areas. Interestingly, paroxysmal activities preceded the onset of epileptic seizures by 7 months, and spike-and-waves by 2 months. After 10 months, he had generalized seizures with fever, and partial seizures on awakening without fever. Interictal EEG showed spike-and-waves on the bilateral frontal areas, and diffuse polyspikes and slow waves were occasionally seen. Though the background activity improved, his consciousness level did not recover probably because the thalamus, basal ganglia, brainstem were damaged more severely than the cerebral cortex.

Studies on cytotoxicity of nickel ions using C3H10T1/2 fibroblast cells

Cytotoxicity of Ni ions were examined using C3H mouse derived 10T1/2 fibroblast cells. It became evident that Ni ions had dose-dependent cytotoxicity. The cell number incubated in DME medium containing 0.04 mM/L Ni ion for 6 days was reduced to half that in control DME medium without Ni. The cell totally disappeared in DME medium containing 2 mM/L Ni ion. The dissolution of Ni ions from Ni-containing metallic restorations must be lower than these concentration levels so that oral tissues might not be damaged. No neoplastic transformation was found on all cells examined.

Blasticidin A derivatives with highly specific inhibitory activity toward aflatoxin production in Aspergillus parasiticus

Blasticidin A (1), an antibiotic, has strong inhibitory activity toward aflatoxin production by Aspergillus parasiticus. We prepared some derivatives of 1 and examined their biological activities. Among them, derivatives 3 and 4 without the tetramic acid moiety of 1 maintained inhibitory activity toward aflatoxin production, but did not show antifungal activity or toxicity. RT-PCR experiments indicated that derivatives 3 and 4 as well as 1 significantly reduced the expression of genes encoding aflatoxin biosynthetic enzymes (pksA, ver-1 and omtA) and a regulatory gene (aflR) in A. parasiticus. These results suggested that derivatives 3 and 4 can inhibit aflatoxin production more specifically than 1 by inhibiting an early step prior to the expression of aflR in the pathway of aflatoxin biosynthesis.

BodyMap: a collection of 3' ESTs for analysis of human gene expression information

BodyMap is a collection of site-directed 3' expressed sequence tags (ESTs) (gene signatures, GSs) that contains the transcript compositions of various human tissues and was the first systematic effort to acquire gene expression data. For the construction of BodyMap, cDNA libraries were made, preserving abundance information and histologic resolutions of tissue mRNAs. By sequencing 164,000 randomly selected clones, 88,587 GSs that represent chromosomally coded transcripts have been collected from 51 human organs and tissues. They were clustered into 18,722 independent 3' termini from transcripts, and more than 3000 of these were not found among ESTs assembled in UniGene (Build 75). Assessment of the prevalence of polyadenylation signals and comparison with GenBank cDNAs indicated that there was no significant contamination by internally primed cDNAs or genomic fragments but that there was a relatively high incidence (12%) of alternative polyadenylation sites. We evaluated the sensitivity and resolution of expression information in BodyMap by in silico Northern hybridization and selection of tissue-specific gene probes. BodyMap is a unique resource for estimation of the absolute abundance of transcripts and selection of gene probes for efficient hybridization-based gene expression profiling.

[2-(O-Phenylalkyl)phenoxy]alkylamines III: Synthesis and selective serotonin-2 receptor binding (2)

A series of 12-(2-phenylethyl)phenoxy]ethylpyrrolidine derivatives were synthesized, and their affinity for serotonin-2 (5-HT2) and dopamine-2 (D2) receptors was examined. Among them, compound 17, (2R,4R)-4-hydroxy-2-[2-[2-[2-(3-methoxyphenyl)ethyl]phenoxylethyl] -1-methylpyrrolidine hydrochloride, showed high 5-HT2 receptor affinity in vitro. This compound was a more potent inhibitor of ex vivo 5-HT-induced platelet aggregation than compound 3, which was previously shown to be more potent than ketanserin (1) and sarpogrelate (2a). However, compound 17 produced gastric irritation in rats. Therefore, we carried out a further derivatization of 17, and compound 45 (R-102444), a lauryl ester prodrug of compound 17, was found to be a promising candidate as an antithrombotic agent. Oral administration of R-102444 produced a marked inhibition of 5-HT-induced ex vivo platelet aggregation, and R-102444 did not cause any gastric irritation. The antiaggregatory effects of R-102444 were more potent than those of sarpogrelate (2a) and its active metabolite, M-1 (2b). In addition, R-102444 exhibited more potent antithrombotic effects than sarpogrelate in a rat photochemically-induced thrombosis model.

Dissociation in conditioned dopamine release in the nucleus accumbens core and shell in response to cocaine cues and during cocaine-seeking behavior in rats

The dopaminergic innervation of the nucleus accumbens is generally agreed to mediate the primary reinforcing and locomotor effects of psychostimulants, but there is less consensus on conditioned dopamine (DA) release during drug-seeking behavior. We investigated the neurochemical correlates of drug-seeking behavior under the control of a drug-associated cue [a light conditioned stimulus (CS+)] and to noncontingent presentations of the CS+ in the core and shell subregions of the nucleus accumbens. Rats self-administered cocaine under a continuous reinforcement schedule in which a response on one of two identical levers led to an intravenous cocaine infusion (0.25 mg/infusion) and a 20 sec light CS+. Response requirements for cocaine and the CS+ were then progressively increased until stable responding was established under a second-order schedule of reinforcement. During microdialysis, rats were presented noncontingently with a set of 10 sec CS+ and neutral tone stimuli (CS-) before and after a 90 min period during which they responded for cocaine under a second-order schedule. Results showed the following: (1) nucleus accumbens DA increased in both the core and shell during intravenous cocaine self-administration; (2) noncontingent presentations of a cocaine-associated CS+ led to increased DA release selectively in the nucleus accumbens core; and (3) extracellular DA levels were unaltered in both core and shell during a protracted period of drug-seeking behavior under the control of the same cocaine-associated cue. These results indicate that the mesolimbic dopamine system is activated after exposure to drug-associated stimuli under specific conditions.