Pathological mechanism and three-dimensional structure of cerebral dissecting aneurysms

OBJECT

The goal of this study was to investigate the pathological mechanism and precise three-dimensional (3D) structure of cerebral dissecting aneurysms in association with their clinical course.

METHODS

Nine aneurysm specimens were excised from eight patients. Of the nine aneurysms, seven arose from the vertebral artery, one from the anterior cerebral artery, and one from the superior cerebellar artery. Eight aneurysms were accompanied with subarachnoid hemorrhage (SAH) and one with infarction. Seven aneurysms were obtained at autopsy and two were obtained during surgery (trapping and bypass). All nine aneurysms were sectioned into serial axial slices measuring 5 to 10 microm in thickness. Taking each slice as an element, we reconstructed the 3D structure of the aneurysm. The true lumen communicated with a pseudolumen through the disrupted portion of the internal elastic lamina (IEL) in all nine aneurysms. The ruptured portion was located just above the disrupted IEL. Two aneurysms had an exit back into the true lumen. but the other seven had no such exit.

CONCLUSIONS

The primary mechanism by which a cerebral dissecting aneurysm is created is by the sudden disruption of the IEL. The plane of dissection extends through the media. The majority of aneurysms have one entrance into the pseudolumen (entry-only type). This type is associated with an unstable clinical course. Some cerebral dissecting aneurysms have both an entrance and exit (entry-exit type). This type of aneurysm occasionally contains a constant flow of blood through the pseudolumen and is clinically more stable than entry-only aneurysms.

Acute phase response in toxicity studies. II. Findings in beagle dogs injected with endotoxin or subjected to surgical operation

Occurrence of characteristic transient changes in WBC counts and fibrinogen values in beagle dogs subjected to single-dose toxicity studies was pointed out in the previous survey (Hoshiya et al., 2001). These changes were thought to belong to the category of "Acute Phase Response (APR)". The purpose of the present study is to compare the APR found in the single-dose toxicity studies surveyed in our previous report with those experimentally produced by intravenous injection of 1 microgram/kg endotoxin (Experiment 1), and surgical treatment (Experiment 2) (intravenous indwelling catheterization). The animals used in Experiment 2 were intravenously injected with 1 microgram/kg endotoxin 2 weeks after the operation (Experiment 3), and the results were compared with those of Experiments 1 and 2. Each experimental group consisted of 5 dogs, and clinical, hematological and blood chemical examinations were performed. Essentially the same changes were observed in response to the intravenous injection with endotoxin and the surgical operation for intravenous indwelling catheterization in beagle dogs. The most remarkable changes common to both treatments were transient increases in the fibrinogen values and WBC counts during the 2 days from Day 1 to Day 2 of the treatment. These changes were preceded by decreases in WBC counts and fibrinogen in Experiments 1 and 3. Increased erythrocyte sedimentation rates were recorded in parallel with the increase in fibrinogen. The results obtained in the present study were similar to those found in dogs treated with various xenobiotic substances in our laboratory. These changes due to different causes were thought to belong to the category of "APR" with the same biological significance as a non-specific defense mechanism.

[Development of three-dimensional stereo viewer for high-resolution data]

In order to visualize high-resolution three-dimensional (3D) data as a stereogram, a real-time volume-rendering system using a hardware graphic board and conventional PC was developed. A 256(3) data set could be visualized at a redrawing rate of 12 Hz, and a 512(3) data set at a rate of 2.5 Hz. It was demonstrated that stereogram visualization using volume graphic hardware architecture potentially enables rapid examination of high-resolution 3D data by changing visualization parameters such as level, window, transfer function for opacity, and color map or coordinate direction.

A novel WD40 repeat protein, WDC146, highly expressed during spermatogenesis in a stage-specific manner

We have cloned a novel cDNA encoding a protein with eight WD repeat motifs and a domain similar to collagen. As the predicted size of the protein was 146 kDa, the gene was named WDC146. Here, we characterized the genomic structure, gene products, and the expression profiles. The human WDC146 gene had 22 exons spanning over 105 kb, and these exons were distributed in three islands intervened by two long introns of around 40 kb. A minimum promoter region was identified within a 0.5 kb 5'-upstream region of exon 1. WDC146 mRNA was most highly expressed in human testis on Northern blot analysis. In mouse tissues, the highest expression was also observed in testis. By in situ hybridization on rat tissues, WDC146 mRNA was detected preferentially in the pachytene stage of spermatocytes in testis, and weakly in white pulp/ marginal band of spleen and in cortex of thymus. WDC146 protein was found to be localized in nucleus. These data implied that WDC146 protein may play important roles in the mechanisms of cytodifferentiation and/or DNA recombination.

Reduction of atherosclerosis despite hypercholesterolemia in lyn-deficient mice fed a high-fat diet

Oxidation and other modifications of serum low-density lipoprotein (LDL) are associated with the development of atherosclerosis, and a scavenger receptor and CD40 signalling are also known to play important roles in the process. We previously showed that the Src family protein-tyrosine kinase Lyn is physically and/or functionally associated with macrophage type-I and type-II class-A scavenger receptors (MSR-A) and CD40. In this study, we addressed whether Lyn is involved in the build-up of serum lipid levels and in atherosclerotic changes. When fed a normal diet, lyn-deficient mice had serum lipid levels that were no different from those of wild-type mice. By contrast, lyn-deficient mice fed a high-fat diet showed serum lipid levels that were much higher than those seen in wild-type mice. Curiously, however, the lyn-deficient mice fed either diet showed no increase in incidence of atherosclerotic lesions compared with wild-type mice. This may be partly explained by our data showing suppression of proliferation of peritoneal macrophages in response to oxidized LDL in the absence of Lyn, and failure of stimulation of the CD40 pathway in lyn-deficient macrophages to induce expression of monocytic chemoattractant protein-1 (MCP-1), which is related to atherosclerosis. These results suggest that Lyn plays an important role in the metabolism of serum lipids and in the development of atherosclerotic lesions on high-fat diets.

[Perspectives on postgenome medicine: Cancer]

Carcinogenesis is a multistep process which is the outcome of the accumulation of genetic and epigenetic events. However, characteristics of cancers, such as drug sensitivity, abilities in invasion and metastasis, are different in each patients, and reliable prediction of those characteristics is not available. DNA microarray and SNP have become the most widely used functional genomics tools. Microarray technology has provided the ability to analyse the expression profiles for thousands of genes, and a wealth of new information that should aid in cancer diagnosis and ultimately in therapy. The SNP project also will generate very variable resources for cancer therapy. The medicine in the next century will be so called 'personalized medicine' based on the new information of patients and diseases.

Arterial dissections of penetrating cerebral arteries causing hypertension-induced cerebral hemorrhage

OBJECT

For the past 130 years, it has been believed that hypertension-induced cerebral hemorrhages are the result of ruptures of microaneurysms or ruptures of arteries that have degenerative changes. The majority of previous investigations have focused on autopsied brain. In this study, the authors attempted to verify the cause of hypertension-induced cerebral hemorrhage by using surgical specimens of the penetrating arteries responsible for the hemorrhages.

METHODS

Between 1997 and 1999, the authors performed pathological studies in surgical specimens of lenticulostriate arteries that had been confirmed during microsurgery to be the cause of hypertension-induced hemorrhage of the putamen. Nineteen lenticulostriate arteries were collected from 12 patients. Fifteen of these arteries were verified as the pathological causes of hemorrhage. They included six arterial dissections, six arterial ruptures with substantial degenerative changes, and three arterial ruptures with few degenerative changes. The pathological findings in the lenticulostriate artery dissections were similar to those of typical arterial dissections in major cerebral arteries.

CONCLUSIONS

To the best of the authors' knowledge, arterial dissections of lenticulostriate arteries have not been identified as a cause of hypertension-induced cerebral hemorrhages. When penetrating arteries are included as causative vessels, cerebral arterial dissections may be much more common than previously thought.

Cloning of TCFL5 encoding a novel human basic helix-loop-helix motif protein that is specifically expressed in primary spermatocytes at the pachytene stage

We have isolated a novel human gene that is expressed specifically in primary spermatocytes in the testis. The cDNA contains an open reading frame of 1356 bp, encoding a 452-amino-acid protein that includes a basic Helix-Loop-Helix (bHLH) motif. The gene, which was mapped to chromosome region 20q13.3-->qter by fluorescence in situ hybridization, consists of six exons and spans approximately 24 kb of genomic DNA. Immunohistochemical staining located the gene product exclusively in cell nuclei of primary spermatocytes at the pachytene stage, but not in those at the leptonema stage. We named this gene TCFL5 (transcription factor-like 5, basic helix-loop-helix). The cell-type and stage-specific expression of TCFL5 indicates that this protein may function in a crucial role in spermatogenesis as a transcription factor by regulating cell proliferation or differentiation of cells through binding to a specific DNA sequence like other bHLH molecules.

Protective effect of human urinary thrombomodulin on ischemia- reperfusion injury in the canine liver

This study was performed to determine whether human urinary soluble thrombomodulin plays a role in liver ischemia-reperfusion injury. Liver ischemia was induced in two groups of dogs. Group 1 was exposed to 60 min ischemia, and group 2 was exposed to 60 min ischemia after preischemic administration of human urinary soluble thrombomodulin. In group 1, the thrombin-antithrombin complex and hyaluronic acid were significantly elevated after ischemia, compared with the preischemic values. While liver issue blood flow and the plasmin-alpha(2)-plasmin inhibitor complex significantly decreased, AST, ALT and m-AST dramatically increased after reperfusion. In group 2, the increase in the thrombin-antithrombin complex and hyaluronic acid was significantly suppressed, and AST, ALT and liver tissue blood flow significantly improved, compared with group 1. Histologically, in group 2, the hepatic tissue structure, including endothelial cells, was relatively intact. These findings suggest that administration of thrombomodulin inhibits endothelial cell injury and coagulopathy and offers protection from liver ischemia-reperfusion injury.

Marriage rate and number of children among young adults with insulin-dependent diabetes mellitus in Japan

The main purpose of our study was to identify the social circumstances and lifestyle of IDDM patients in Japan. The present study focused on the marriage status of both men and women with IDDM as well as the number of children of women with IDDM. A questionnaire was sent to hospitals across the country. Doctors handed it or mailed it to IDDM patients aged 18 years or older. Unsigned answer sheets were returned directly by the patients. Data on the marriage rate and number of children were obtained, and possible factors affecting these indices were assessed. One thousand and thirteen patients (354 men and 659 women) answered the questionnaire. Both men and women with IDDM were less likely to be married in comparison with age-matched Japanese. The number of children of married IDDM women in various age groups was also lower in comparison with the general Japanese female population. Several factors other than diabetes complications including job discrimination, high medical costs, and psychological pressures, were thought to be responsible for these results.

Identification of Rad51 alteration in patients with bilateral breast cancer

The human Rad51 gene, HsRAD51, is a homolog of RecA of Escherichia coli and functions in recombination and DNA repair. BRCA1 and BRCA2 proteins form a complex with Rad51, and these genes are thought to participate in a common DNA damage response pathway associated with the activation of homologous recombination and double-strand break repair. Additionally, we have shown that the pattern of northern blot analysis of the RadS gene is closely similar to those of the BRCA1 and BRCA2 genes. It is therefore possible that alterations of the Rad51 gene may be involved in the development of hereditary breast cancer. To investigate this possibility, we screened Japanese patients with hereditary breast cancer for Rad51 mutations and found a single alteration in exon 6. This was determined to be present in the germline in two patients with bilateral breast cancer, one with synchronous bilateral breast cancer and the other with synchronous bilateral multiple breast cancer. In both patients, blood DNAs showed a G-to-A transition in the second nucleotide of codon 150, which results in the substitution of glutamine for arginine. As this alteration was not present in any patients with breast or colon cancer examined, we assume that this missense alteration is likely to be a disease-causing mutation.

[Genetic epidemiology of hereditary tumor]

The last decade has seen many great successes in isolating genes involved in inherited disease, a process that is now scaled up by Human Genome Project. The identification of genes responsible for hereditary tumors has made it possible to do the genetic diagnosis of hereditary tumors. However, the benefits and limits of genetic testing for cancer susceptibility are different in each hereditary tumor. It is important to continue the analysis of significance(frequency and penetrance) of mutations of cancer predisposition genes and to make clear the genotype-phenotype and other correlation. Hereditary breast cancer and hereditary non-polyposis colorectal cancer are reviewed and the significance of genetic epidemiology of hereditary tumor is discussed.

Magnetization transfer histogram analysis of monosymptomatic episodes of neurologic dysfunction: preliminary findings

BACKGROUND AND PURPOSE

Patients presenting with a monosymptomatic episode of neurologic dysfunction (MEND) have a high probability of developing multiple sclerosis (MS). Our study was designed to determine whether magnetization transfer (MT) histogram analysis could predict the development of MS for a cohort of patients presenting with a MEND.

METHODS

Eleven patients with a MEND and 21 age-matched control volunteers underwent MR imaging. Six patients underwent serial MR examinations. MT ratio histogram peak height (MTRHPH) and the location of the MT ratio histogram peak (LOC MTRHP) were determined for patients and control volunteers. T2 lesion volume was also calculated. Patients were clinically followed up for 587 +/- 308 days to determine or rule out the development of MS.

RESULTS

Three patients went on to develop MS. There was no statistically significant difference in the MTRHPH (P = .65) and the LOC MTRHP (P = .71) between patients and control volunteers. For those patients who underwent multiple examinations, no statistically significant differences in the MTRHPH (P = .64), LOC MTRHP (P =.58), and T2 lesion volume (P = .47) were seen. There were no statistically significant correlations between any of the parameters studied.

CONCLUSION

We found no difference in MT histogram parameters among control volunteers, patients with a MEND without MS, and patients with a MEND who went on to a diagnosis of MS. Our preliminary findings suggest that there may not be a substrate of disease in the normal-appearing white matter that is predictive of the development of MS.

Nuclear localization signals of the BRCA2 protein

BRCA2 is a tumor suppressor gene whose germline mutations increase the lifetime risk of breast cancer. BRCA2 encodes a large nuclear protein involved in DNA repair, but the location of its functional domain has been unclear. Here, we report nuclear localization signals (NLSs) of the BRCA2 protein. By expressing various portions of the BRCA2 protein tagged with enhanced green fluorescent protein in HeLa cells, we show that the C-terminal domain is necessary for nuclear localization. Two regions in the C-terminal domain were identified with functional NLSs by site-directed mutagenesis analyses. The NLSs locate between the germline mutation found in the most downstream position and the polymorphic stop codon, suggesting that defects in the proper nuclear transport of the BRCA2 protein are causative of carcinogenesis. Our data thus provide a possible explanation for the high frequency of frame-shift and nonsense mutations in BRCA2 of hereditary breast cancer patients.

Potential role of BRCA2 in a mitotic checkpoint after phosphorylation by hBUBR1

BRCA2, a gene responsible for inherited susceptibility to breast cancer in a number of families, is thought to be critical for replication and repair of DNA during S-phase. To elucidate the physiological functions of BRCA2, we used a yeast two-hybrid system to screen for proteins that could associate with BRCA2. Here we report interaction of BRCA2 with a mitotic checkpoint protein, hBUBR1, and its phosphorylation by hBUBR1 in vitro. After cotransfection of BRCA2 and hBUBR1 expression vectors into the COS7 cell line, both proteins were stained together in the nuclei of cells whose spindle fibers were disrupted, but not in undamaged cells. Treatment with vincristine, which disrupts microtubules, significantly increased expression of both hBUBR1 and BRCA2 in the MCF7 cells. The results suggest that BRCA2 protein might be involved in a mitotic checkpoint in vivo after it has been phosphorylated by hBUBR1.

Parathyroid hormone-activated volume-sensitive calcium influx pathways in mechanically loaded osteocytes

This paper documents for the first time a volume-sensitive Ca(2+) influx pathway in osteocytes, which transmits loading-induced signals into bone formation. Stretch loading by swelling rat and chicken osteocytes in hypo-osmotic solution induced a rapid and progressive increase of cytosolic calcium concentration, [Ca(2+)](i). The influx of extracellular Ca(2+) explains the increased [Ca(2+)](i) that paralleled the increase in the mean cell volume. Gadolinium chloride (Gd(3+)), an inhibitor of stretch- activated cation channels, blocked the [Ca(2+)](i) increase caused by hypotonic solutions. Also, the expression of alpha1C subunit of voltage-operated L-type Ca(2+) channels (alpha1C) is required for the hypotonicity-induced [Ca(2+)](i) increase judging from the effect of alpha1C antisense oligodeoxynucleotides. Parathyroid hormone (PTH) specifically potentiated the hypotonicity-induced [Ca(2+)](i) increase in a dose-dependent manner through the activation of adenyl cyclase. The increases induced by both PTH and hypotonicity were observed primarily in the processes of the osteocytes. In cyclically stretched osteocytes on flexible-bottomed plates, PTH also synergistically elevated the insulin-like growth factor-1 mRNA level. Furthermore, Gd(3+) and alpha1C antisense significantly inhibited the stretch-induced insulin-like growth factor-1 mRNA elevation. The volume-sensitive calcium influx pathways of osteocytes represent a mechanism by which PTH potentiates mechanical responsiveness, an important aspect of bone formation.

Biological activity of alkyl 2-(acylthio)benzoates

Of a series of synthetic alkyl 2-(acylthio)benzoate (1-20), all the derivatives except for n-butyl 2-butyrylthiobenzoate (18) and n-butyl 2-n-valerylthiobenzoate (20) showed clear phytogrowth-inhibitory activity. All the compounds tested except for methyl 2-butyrylthiobenzoate (3) exhibited cytotoxic activity on mouse splenic T cells. Strong phytogrowth-inhibition and cytotoxic activity were found with 1, 6, 11 and 16 with an acetylthio group at C-2, suggesting that the acetyl group seems to play an important role in both activities of alkyl 2-(acylthio)benzoates. Among them, methyl 2-acetylthiobenzoate (1) was the strongest inhibitor. On the other hand, potent inhibition of prolyl endopeptidase was exhibited by 2, 7, 12 and 17 with a propionylthio group at C-2. These findings imply that a propionyl group might be useful for increasing the inhibitory activity against on prolyl endopeptidase.

Novel missense mutations in the glutamate dehydrogenase gene in the congenital hyperinsulinism-hyperammonemia syndrome

OBJECTIVES

The objectives of this study were to clarify the involvement of the glutamate dehydrogenase gene in congenital hyperinsulinemia-hyperammonemia syndrome (CHHS) and the relationships between the mutation of the gene and clinical severity.

STUDY DESIGN

Five unrelated Japanese patients (3 girls and 2 boys) with CHHS were investigated. All patients had convulsions or loss of consciousness resulting from hypoglycemia at less than 1 year of age. We examined mutations of the glutamate dehydrogenase gene using genomic or reverse-transcriptase polymerase chain reactions, followed by direct sequencing.

RESULTS

We identified heterozygous missense mutations in all patients. Three patients had a previously identified mutation (C-->T at nt 1506) at codon 445 in the allosteric domain. Two novel missense mutations were identified in the other patients. These mutations included a change of A-->C at nt 1059 and a change of G-->A at nt 966, within the catalytic domain of the glutamate dehydrogenase gene. The locus of the mutations was not associated with the severity of hypoglycemia.

CONCLUSIONS

Our results suggest that structural aberrations of not only the allosteric domain but also the catalytic domain of the glutamate dehydrogenase protein, caused by missense mutations, can result in the development of CHHS.

Comparison of short inversion time inversion recovery (STIR) and fat-saturated (chemsat) techniques for background fat intensity suppression in cervical and thoracic MR imaging

The purpose of this study was to compare short inversion time inversion recovery (STIR) fast spin-echo (FSE), and fat-saturated T2-weighted FSE sequences in terms of uniformity of fat suppression and lesion conspicuity for magnetic resonance (MR) imaging of the neck and thorax. STIR FSE and fat-saturated T2-weighted FSE images were scored for uniformity of fat suppression (n = 40) and lesion conspicuity (n = 35). Five-point rank score analyses were utilized by three experienced radiologists. The mean scores of STIR and fat-saturated FSE techniques for uniformity of fat suppression were 4.3 and 2.3, respectively (P < 0.0001). The mean scores of STIR and fat-saturated FSE techniques for lesion conspicuity were 4.2 and 3.5, respectively (P < 0.0001). Insufficient fat suppression was prominent in the mandible, supraclavicular region, anterior mediastinum, epipericardial fat, and subdiaphragmatic fat. In addition, fat-saturated T2-weighted FSE showed inadvertent water suppression in 25%. The STIR FSE technique was superior to the fat-saturated FSE technique for cervical and thoracic MR imaging.

Clinicopathological studies of odontoma in 47 patients

A 14-year retrospective study was performed on 47 odontomas from the files of the 1st Department of Oral and Maxillofacial Surgery at Nihon University School of Dentistry. Fifty-seven percent of the patients were male and 42.6% were female. The age distribution was 8 to 48 years with a mean age of 22 +/- 9.0 years. There were no particular symptoms associated with the odontomas, and 63.8% of our patients had no symptoms. However, 12 patients complained of swelling and 9 of pain. The tumor was found in the maxilla in 42.6% and in the mandible in 57.4%. According to the WHO histological type classification, 53.2% of the tumors were classified as compound odontoma and 46.8% as complex odontoma. The size of the tumor ranged from 5 mm to 42 mm in diameter. The average complex odontoma was much bigger than the average compound odontoma. Ghost cells were found 11 cases in our series. In addition, odontogenic epithelium was found in 16 cases. Twenty seven patients had impacted teeth in association with odontoma and 24 of the 27 teeth were removed at the time of surgical enucleation of the tumor, while 3 cases were treated by orthodontically assisted eruption. There was no recurrence in any of the studied cases.

Rapid progression of pituitary hyperplasia in humans with primary hypothyroidism: demonstration with MR imaging

PURPOSE

To use magnetic resonance (MR) imaging to evaluate the morphologic changes of the pituitary gland during the development of hypothyroidism.

MATERIALS AND METHODS

Fourteen patients who had undergone thyroidectomy were evaluated before radioactive iodine 131 therapy. In each patient, MR imaging and measurement of serum hormone levels were performed twice: 5 weeks before 131I treatment as the "euthyroid state" with thyroid hormone supplementation and on the day of 131I treatment as the "hypothyroid state" after a 3-week depletion of thyroid hormone supplements. Nine healthy volunteers also underwent MR imaging twice at an interval of 5 weeks. Pituitary volume and the relative signal intensity ratio of the anterior pituitary to the pons were measured. The shape and signal intensity of the pituitary gland were also visually assessed. The paired Student t test was used to evaluate the significance of the data. A P value less than .05 indicated a statistically significant difference.

RESULTS

The patients had significantly larger pituitary volume in the hypothyroid state than in the euthyroid state both quantitatively (P < .001) and visually. No significant differences were found in the relative signal intensity ratios of the anterior pituitary to the pons. In healthy volunteers, no significant differences in pituitary volumes or signal intensity were found between the two MR images.

CONCLUSION

Rapid progression of hyperplasia of the anterior pituitary may occur with acute development of hypothyroidism.