Early development of amphioxus nervous system with special reference to segmental cell organization and putative sensory cell precursors: a study based on the expression of pan-neuronal marker gene Hu/elav.

The development of the nervous system of amphioxus was investigated at the cellular level based on the expression of the pan-neuronal marker gene Hu/elav. In situ hybridization analysis showed that an amphioxus Hu/elav homolog (AmphiHu/Hel) was expressed in individual cells within the neural plate, but the cells exhibited no obvious arrangements in early embryos without distinct somites. However, in neurulae with somites, AmphiHu/Hel-positive cells were clustered along the D-V axis in close register with the boundaries of somites, resulting in reiterated cell arrangements that became evident along the neuraxis. Furthermore, AmphiHu/Hel-positive cell clusters appeared one by one along with the development of underlying somites. Double-staining in situ hybridization analysis with the islet gene revealed that the cell clusters contain presumptive motoneurons. In addition, AmphiHu/Hel expression was also observed outside the CNS, probably in the epithelial ectoderm, suggesting that amphioxus has a large number of putative sensory cell precursors as early as the early neurula stage. Taking recent gene expression studies and anatomical studies into consideration, we discuss ontogenetic and phylogenetic features of the amphioxus nervous system.

Gene expression profiles in Ciona intestinalis tailbud embryos.

A set of 3423 expressed sequence tags derived from the Ciona intestinalis tailbud embryos was categorized into 1213 independent clusters. When compared with DNA Data Bank of Japan database, 502 clusters of them showed significant matches to reported proteins with distinct function, whereas 184 lacked sufficient information to be categorized (including reported proteins with undefined function) and 527 had no significant similarities to known proteins. Sequence similarity analyses of the 502 clusters in relation to the biosynthetic function, as well as the structure of the message population at this stage, demonstrated that 390 of them were associated with functions that many kinds of cells use, 85 with cell-cell communication and 27 with transcription factors and other gene regulatory proteins. All of the 1213 clusters were subjected to whole-mount in situ hybridization to analyze the gene expression profiles at this stage. A total of 387 clusters showed expression specific to a certain tissue or organ; 149 showed epidermis-specific expression; 34 were specific to the nervous system; 29 to endoderm; 112 to mesenchyme; 32 to notochord; and 31 to muscle. Many genes were also specifically expressed in multiple tissues. The study also highlighted characteristic gene expression profiles dependent on the tissues. In addition, several genes showed intriguing expression patterns that have not been reported previously; for example, four genes were expressed specifically in the nerve cord cells and one gene was expressed only in the posterior part of muscle cells. This study provides molecular markers for each of the tissues and/or organs that constitutes the Ciona tailbud embryo. The sequence information will also be used for further genome scientific approach to explore molecular mechanisms involved in the formation of one of the most primitive chordate body plans.

The expression of nonchordate deuterostome Brachyury genes in the ascidian Ciona embryo can promote the differentiation of extra notochord cells.

The notochord is a structure present in all chordates and its development requires the transcription of Brachyury. While previous studies have shown that Brachyury is essential for notochord formation in vertebrate embryos, this gene is also expressed during the embryogenesis of nonchordate deuterostomes, hemichordates and echinoderms. Here we report that nonchordate deuterostome Brachyury genes can trigger the differentiation of extra notochord cells when these genes are ectopically expressed in ascidian embryos. The 2.6 kb upstream region of fork head gene (Ci-fkh) of Ciona intestinalis promotes the tissue-specific expression of a reporter gene in endoderm, notochord and nerve cord. By taking advantage of this promoter, we misexpressed the Brachyury gene of ascidian (Ci-Bra), cephalochordate amphioxus (Am(Bb)Bra2), hemichordate acorn worm (PfBra), and echinoderm sea urchin (SpBra), in Ciona embryos. The misexpression of not only the chordate Brachyury, but also the nonchordate deuterostome Brachyury, resulted in the transformation of presumptive endodermal cells into notochord cells. This was confirmed by in situ hybridization experiments using four different notochord-specific probes from Ciona that have different temporal expression patterns. RT-PCR analyses indicated that Ci-Bra was not upregulated by the product of Am(Bb)Bra2, PfBra or SpBra. In situ hybridization showed no ectopic expression of Ci-Bra in the manipulated embryos. These results suggest that the introduction of nonchordate deuterostome Brachyury genes into ascidian embryos can trigger the differentiation of notochord cells in ascidian embryos. Evolutionary alteration in the genetic circuitry, especially downstream of this transcription factor, seems critical for the evolution of notochord and chordate body plan.

Indications and problems of intracranial stenting. Report of two cases.

SUMMARY: There have been few reports of stenting in the intracranial arteries.We used coronary stents in the chronically occluded intracranial vertebral artery and stenosis of internal carotid artery by the external force, and good blood flow were resumed. Stenosis in the intracranial arteries is also a good indication for stent placement when it is due to chronic total occlusion or artery compression by external force. But stent placement in the intracranial arteries has some problems. Stent placement in the intracranial artery is indicated only when the site of stent placement has a diameter of 3 mm or more, is a relatively linear portion of the vertebrobasilar artery or the internal carotid artery proximal to the C3 segment, and does not branch off perforating arteries or is already completely occluded.

Evolutionary alterations of the minimal promoter for notochord-specific Brachyury expression in ascidian embryos.

The Brachyury genes of two divergent ascidians, As-T of Halocynthia roretzi and Ci-Bra of Ciona intestinalis, are expressed exclusively in notochord precursor cells. A previous study showed that the notochord-specific expression of Ci-Bra is controlled by a minimal promoter that is composed of three distinct regions: a region responsible for repression of expression in non-notochord mesoderm cells, a region for activation of expression in notochord cells, and a region for activation of expression in non-notochord mesoderm cells, distal to proximal to the transcription initiation site, respectively. We examined various deletion constructs of the As-T/lacZ fusion gene and demonstrate that a module between -289 and -250 bp of the 5'-flanking region is responsible for notochord-specific expression of the reporter gene. Gel-shift assays suggested the binding of nuclear protein(s) to this module. The 5'-flanking region of As-T contains a potential T-binding motif (-ACCTAGGT-) around -160 bp. Deletion of this motif from the p(-289)As-T/lacZ diminished the reporter gene expression. In addition, coinjection of p(-289)As-T/lacZ and synthetic As-T mRNA resulted in ectopic expression of lacZ in non-notochord cells, suggesting that the T-binding motif is responsible for autoactivation of the gene. These findings revealed striking differences between the minimal promoters of As-T and Ci-Bra so far revealed, with respect to their notochord-specific expression. Furthermore, reciprocal injections of reporter gene constructs, namely As-T/lacZ into Ciona eggs and Ci-Bra/lacZ into Halocynthia eggs, suggest alterations in the cis-regulatory elements and trans-activation factors that have occurred during evolution of the two ascidian species.

Exogenous recombinant human IL-12 augments MHC class I antigen expression on human cancer cells in vitro.

We investigated whether expressions of MHC class I and class II antigens relevant to tumor antigen presentation were changed on human tumor cells cultured with or without recombinant human IL-12(rhIL-12). We showed that the expression of MHC class I antigen on UTC-8, 28-1Cl and SBC-3 cells was augmented when these cancer cells were cultured with rhIL-12. The expression of class II antigen was slightly raised on UTC-8 and 28-1Cl cells by rhIL-12, but not enhanced on SBC-3 cells. These results suggest that rhIL-12 may provide possible enhancement of immunologic tumor recognition, and cytotoxic activity of lymphocytes against tumors through the enhanced expression of MHC class I antigen.

CT angiography with helical CT in the assessment of acute stage of subarachnoid hemorrhage.

PURPOSE: We evaluated the usefulness of helical CT in the preoperative assessment of ruptured cerebral aneurysms during the acute stage of subarachnoid hemorrhage (SAH). METHODS: Nine patients with 13 aneurysms were included in this study. Helical CT scanning was performed before preoperative angiography. The section thickness and the table-movement speed were 1-2 mm/sec. Helical CT scanning was started 20 sec after the start of injection of 100 ml of contrast agent at a rate of 3 ml/sec. RESULTS: The average CT value of SAH was 51.9 Hounsfield units (HU) and that of the aneurysm was 191.7 HU. Nine of 13 aneurysms greater than 3.0 mm in diameter were identified by three-dimensional CT angiography (3DCTA). In seven cases, the information provided by 3DCTA images, maximum intensity projection images, and multiplanar images, was very useful in surgical planning, providing information concerning the configuration of the neck and relationships between the aneurysm and brain parenchyma. Four aneurysms in two cases were not depicted by 3DCTA because they were located outside the imaging volume. This problem was overcome by changing the imaging volume according to the extent of origin of SAH. CONCLUSION: We conclude that helical CT in patients with SAH is useful for surgical planning, providing valuable information that cannot be obtained by conventional angiography.

The role of three-dimensional computed tomography in the management of maxillofacial bone fractures.

The findings of three-dimensional computed tomography (3DCT) and two-dimensional computed tomography (2DCT) with helical CT scanning were compared for 21 patients with maxillofacial bone fractures. The results of this study suggest that the 3DCT evaluation can be divided into 3 groups. The first group, in which 3DCT is superior to 2DCT, includes severe complicated midface fractures, for example, tripod fractures and complicated maxillary bone fractures. The second group, in which 3DCT is equal to 2DCT, includes simple fractures, for example, nasal bone fractures and isolated zygomatic fractures. In this group, patients and their families could easily understand the nature of the fracture and clinical course shown by 3DCT as compared with conventional X-ray and 2DCT. The third group, in which 3DCT is inferior to 2DCT, includes blowout fractures. Although 3DCT does not provide additional information is blowout fractures, helical scanning permits clear observation of multiplanar images without artifacts arising from metal prostheses by excluding lower slices during image reconstruction. We conclude that 3DCT provides useful information, especially in regard to the extent of complex fracture lines, as in tripod fractures.

Collagen formation at the tooth-cell interface: comparative ultrastructural study on the effect of partial demineralization of cementum with dentin.

In order to compare the effect of partial demineralization with root planing and partial demineralization of cementum with that of dentin on healing, the ultrastructural morphology of the interface between the layer of human periodontal ligament-derived, fibroblast-like cells (HPF) and the treated root surface was studied in an in vitro culture system. Sixty (60) pairs made from transversally-cut root slices, 500 microns thick, were obtained from extracted human periodontally diseased teeth. Thirty (30) pairs of the root slices were preliminarily root planed (RP). The remaining half were root planed and then partially demineralized in a solution of citric acid (RP+CA). The opposite surface of paired slices was made uniform by using either cementum or dentin. Consequently, all root slices were classified into four experimental groups: RP-cementum and RP-cementum pairs (group 1), RP-dentin and RP-dentin pairs (group 2), RP+CA-cementum and RP+CA-cementum pairs (group 3), and RP+CA-dentin and RP+CA-dentin pairs (group 4). Each pair of root slices was placed on the floor of a 35-mm culture dish. HPF were seeded at a concentration of 4 x 10(5) cells/dish. Co-cultures of HPF and the root slices were examined using phase contrast and electron microscope after 4, 6, and 10 weeks. Electron-dense material covered non-demineralized root surfaces and the lining cells in accumulating cell layers were oriented parallel to the root surface and attached to the material in groups 1 and 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationships between the slope of the oxygen equilibrium curve and the cooperativity of hemoglobin as analyzed using a normalized oxygen pressure scale.

The oxygen equilibrium curve (OEC) for hemoglobin, which is usually expressed as a S vs. P plot, was expressed by normalizing P by Pdmax, where S is oxygen saturation, P is partial pressure of oxygen, and Pdmax is P at which the slope of the usual OEC is maximized. The maximal slope of normalized OEC gives Pdmax.S'max, where S'max is the maximal slope of the usual OEC, a measure for the oxygen transport efficiency of hemoglobin. Here, the term "efficiency" is used in the sense that the oxygen release from hemoglobin becomes more sensitive to oxygen pressure changes as S'max becomes larger. An analysis using 38 sets of published oxygen equilibrium data for human adult hemoglobin under various experimental conditions showed that (a) expressing OEC by means of S vs. P/Pdmax or S vs. log P is advantageous for analyzing the slope of OEC compared to usual S vs. P plot and (b) while the OEC differs depending on experimental conditions, S'max varies in close linear correlation to nmax (the maximal slope of the Hill plot which measures oxygen binding cooperativity), and Pdmax.S'max is almost equal to nmax/4. Thus, the parameter expressing oxygen transport efficiency is closely related to the parameter expressing oxygen binding cooperativity.

Sigmoid shape of the oxygen equilibrium curve and the P50 of human hemoglobin.

The fractional saturation of hemoglobin with oxygen was plotted against P/P50 and the slope of the abscissa at 1 was calculated for 38 OEC data sets of human Hb A. There was a linear correlation between the slope and the Hill coefficient (nmax), and the slope was about one-fourth that of nmax. This implies that the slope of the abscissa at 1 of Y vs P/P50 plot can provide information about the magnitude of cooperativity in hemoglobin oxygen binding.

Cerebral cysticercosis: a case report.

A case of cerebral cysticercosis is reported in a 49-year-old female who presented with headache, nausea, and vomiting. Lumbar CSF showed the findings of mild aseptic meningitis. CT scan revealed an enlargement of the left ambient cistern and a small cystic lesion in the left frontal cortex. MRI demonstrated multilobular cysts in the left ambient cistern with enhancement of their capsules, which compressed and distorted the midbrain. The cysts were surgically excised, and histological examination of the specimen disclosed characteristic features of cysticercus with viable larva. An excellent value of MRI in the diagnosis of intracisternal cysticercosis is emphasized.

The permeability change of major cerebral arteries in experimental vasospasm.

The influence of vasospasm on the permeability of the major cerebral arteries was studied using horseradish peroxidase (HRP). Experimental vasospasm was produced in canine basilar arteries by successive injections, 2 days apart, of autologous blood into the cisterna magna. HRP was injected intravenously or intracisternally 48 hours after the second injection of autologous blood, and all animals were killed by perfusion fixation 60 minutes after the injection of HRP. The distribution of HRP was observed by transmission electron microscopy. In 10 dogs injected intracisternally with HRP, 5 control dogs demonstrated a moderate amount of HRP in the intermuscular space through the adventitia. Five dogs with subarachnoid hemorrhages (SAHs) showed a moderate amount of HRP in the intermuscular space. In 11 dogs injected intravenously with HRP, 5 control dogs showed no leakage of HRP into vessel walls. Six dogs with SAHs showed HRP in the interendothelial space. These findings suggest that, despite SAHs, HRP seems to be able to circulate in the cerebrospinal fluid and makes contact with the cerebral vessels. This study suggests the possibility that spasmogenic substances may penetrate the vessel wall from the extraluminal side more easily than from the intraluminal side.

[Arterial infusion chemotherapy and embolization in unresectable hepatocellular carcinoma using an intraarterial catheter].

We performed arterial infusion chemotherapy and embolization on 22 patients with unresectable hepatocellular carcinoma via an intraarterial catheter, which was inserted in the hepatic artery under laparotomy. The administration frequency of intraarterial chemotherapy on a patient was 1 to 155 with a median of 17, while that of embolization was 1 to 6 with a median of 2.5. The maximal and average durations of a catheter in place were 15 and 4 months, respectively. The survival rates were 50% in one year, 18% in two years, and 12% in three years. Insertion technique and management of the catheter are relatively safe and easy, so catheterization of the hepatic artery would enable us to develop new treatment modalities.

Inhibitory effect of laser irradiation on dermal syngeneic tumor growth in mice.

Mice (C57BL/6) with established intradermal tumors (melanoma B-16 or glioma 203G1) and inbred Swiss mice (SWM/Ms) with established intradermal tumors (3-methylcholanthrene-induced sarcoma) were treated by either surgical excision or laser irradiation. Laser irradiation is effective in preventing the growth of dermal melanoma, and laser therapy may be more efficacious than surgical therapy for induction of a reaction against melanoma in mice. The results also suggest that determination of a suitable laser wavelength may be required to obtain a good therapeutic effect on each tumor.

Therapeutic effects of tiopronin on chronic hepatitis: a double-blind clinical study.

The efficacy of tiopronin (2-mercaptopropionyl glycine) 600 mg daily in the treatment of chronic active or chronic persistent hepatitis has been assessed in a double-blind controlled clinical trial of 12 weeks involving 165 Japanese patients with histologically proven disease. Treatment with the drug was associated with a significant improvement in abnormalities of serum transaminase and gamma glutamyl transpeptidase, with reversion towards baseline values on stopping the drug. Improvement was independent of the histological classification of the disease, or HBsAg status. The drug was well tolerated with few side-effects. The results of this short-term study indicate that tiopronin may be of value in the treatment of chronic hepatitis.