Randomized clinical trial of hepatectomy using intermittent pedicle occlusion with ischaemic intervals of 15 versus 30 minutes

Background

The optimal ischaemic interval during hepatectomy with intermittent pedicle occlusion (IPO) remains to be established. The aim of the present randomized clinical trial was to compare the short-term outcome of hepatectomy using IPO with an ischaemic interval of 15 versus 30 min.

Methods

Between October 2002 and September 2004, 108 consecutive patients scheduled to undergo hepatectomy without bilioenterostomy were enrolled. During liver transection, IPO was performed with an ischaemic interval of either 15 min with 5 min of reperfusion (standard group, SG) or 30 min with 5 min of reperfusion (prolonged group, PG). After randomization and subsequent exclusion of certain patients, 44 patients in the SG and 48 in the PG were analysed.

Results

The mean(s.d.) bilirubin ratio (serum total bilirubin level on day 2 after operation divided by the preoperative level) was 1·6(0·8) in the SG and 1·7(0·8) in the PG (P = 0·874). The transection area per unit transection time was significantly greater in the latter group (median (range) 1·0 (0·4–2·1) versus 0·8 (0·0–1·5) cm2/min; P = 0·046).

Conclusion

There was no difference in the bilirubin ratio when IPO was carried out for 30 or 15 min. By extension of IPO to 30 min, a greater resection area per unit time was possible with preservation of remnant liver function.

Sec16 is a determinant of transitional ER organization

BACKGROUND

Proteins are exported from the ER at transitional ER (tER) sites, which produce COPII vesicles. However, little is known about how COPII components are concentrated at tER sites. The budding yeast Pichia pastoris contains discrete tER sites and is, therefore, an ideal system for studying tER organization.

RESULTS

We show that the integrity of tER sites in P. pastoris requires the peripheral membrane protein Sec16. P. pastoris Sec16 is an order of magnitude less abundant than a COPII-coat protein at tER sites and seems to show a saturable association with these sites. A temperature-sensitive mutation in Sec16 causes tER fragmentation at elevated temperature. This effect is specific because when COPII assembly is inhibited with a dominant-negative form of the Sar1 GTPase, tER sites remain intact. The tER fragmentation in the sec16 mutant is accompanied by disruption of Golgi stacks.

CONCLUSIONS

Our data suggest that Sec16 helps to organize patches of COPII-coat proteins into clusters that represent tER sites. The Golgi disruption that occurs in the sec16 mutant provides evidence that Golgi structure in budding yeasts depends on tER organization.

Comparison of the protein-unfolding pathways between mitochondrial protein import and atomic-force microscopy measurements

Many newly synthesized proteins have to become unfolded during translocation across biological membranes. We have analyzed the effects of various stabilization/destabilization mutations in the Ig-like module of the muscle protein titin upon its import from the N terminus or C terminus into mitochondria. The effects of mutations on the import of the titin module from the C terminus correlate well with those on forced mechanical unfolding in atomic-force microscopy (AFM) measurements. On the other hand, as long as turnover of the mitochondrial Hsp70 system is not rate-limiting for the import, import of the titin module from the N terminus is sensitive to mutations in the N-terminal region but not the ones in the C-terminal region that affect resistance to global unfolding in AFM experiments. We propose that the mitochondrial-import system can catalyze precursor-unfolding by reducing the stability of unfolding intermediates.

Comparison of capsule endoscopy and enteroscopy with the double-balloon method in patients with obscure bleeding and polyposis

BACKGROUND AND STUDY AIMS

Video capsule endoscopy and double-balloon enteroscopy (DBE) are novel methods of enteroscopy. The aim of this investigation was to compare the value of CE and DBE in the diagnosis of small-intestinal pathology.

PATIENTS AND METHODS

Thirteen patients with gastrointestinal bleeding of obscure origin and nine patients with known gastrointestinal polyposis were examined using antegrade or retrograde DBE, and the most distal or proximal site in the explored small intestine was marked by submucosal injection of sterilized ink. The patients were then evaluated by CE. Video images obtained by CE were reviewed by an observer who was blinded to the DBE findings.

RESULTS

DBE identified positive findings in 12 patients (54.5 %). CE identified positive findings in the area explored by DBE in eight patients (36.4 %), and in the unexplored area in 11 patients (50.0 %). The overall diagnostic yield in the area explored by DBE did not differ between the two procedures. The enteroscopic findings in the area explored by DBE were concordant in 12 of 13 patients with gastrointestinal bleeding of obscure origin. In patients with polyposis, the diagnoses were discordant in three patients, in whom CE failed to detect any polyp. In two of three polyposis patients with concordant positive findings, DBE detected a larger number of polyps than CE did.

CONCLUSIONS

DBE appears to be superior to CE in the diagnosis of small-intestinal polyps, whereas the value for diagnosing gastrointestinal bleeding of obscure origin is similar in the two procedures.

The Phosphate Carrier Has an Ability to be Sorted to either the TIM22 Pathway or the TIM23 Pathway for Its Import into Yeast Mitochondria

Most mitochondrial proteins are synthesized in the cytosol, imported into mitochondria via the TOM40 (translocase of the mitochondrial outer membrane 40) complex, and follow several distinct sorting pathways to reach their destination submitochondrial compartments. Phosphate carrier (PiC) is an inner membrane protein with 6 transmembrane segments (TM1-TM6) and requires, after translocation across the outer membrane, the Tim9-Tim10 complex and the TIM22 complex to be inserted into the inner membrane. Here we analyzed an in vitro import of fusion proteins between various PiC segments and mouse dihydrofolate reductase. The fusion protein without TM1 and TM2 was translocated across the outer membrane but was not inserted into the inner membrane. The fusion proteins without TM1-TM4 were not inserted into the inner membrane but instead translocated across the inner membrane. Functional defects of Tim50 of the TIM23 complex caused either by depletion of the protein or the addition of anti-Tim50 antibodies blocked translocation of the fusion proteins without TM1-TM4 across the inner membrane, suggesting that lack of TM1-TM4 led to switch of its sorting pathway from the TIM22 pathway to the TIM23 pathway. PiC thus appears to have a latent signal for sorting to the TIM23 pathway, which is exposed by reduced interactions with the Tim9-Tim10 complex and maintenance of the import competence.

Mitochondrial Protein Import

Protein translocation across the outer mitochondrial membrane is mediated by the translocator called the TOM (translocase of the outer mitochondrial membrane) complex. The TOM complex possesses two presequence binding sites on the cytosolic side (the cis site) and on the intermembrane space side (the trans site). Here we analyzed the requirement of presequence elements and subunits of the TOM complex for presequence binding to the cis and trans sites of the TOM complex. The N-terminal 14 residues of the presequence of subunit 9 of F(0)-ATPase are required for binding to the trans site. The interaction between the presequence and the cis site is not sufficient to anchor the precursor protein to the TOM complex. Tom7 constitutes or is close to the trans site and has overlapping functions with the C-terminal intermembrane space domain of Tom22 in the mitochondrial protein import.

Small invasive colonic cancer occurring in a hyperplastic polyp

We report a case of advanced colon cancer which was supposed to have arisen from a hyperplastic polyp in a 68-year-old man. Colonoscopy revealed a depressed reddish area with a surrounding elevated lesion that was of a faded color compared with the normal mucosa. After the mucosal surface had been sprayed with crystal violet dye, magnifying colonoscopy showed an amorphous area in the central depression and the surrounding, slightly elevated lesion had an asteroid pattern. The depressed area was therefore considered to be a colonic cancer surrounded by a hyperplastic polyp. Endoscopic ultrasonography showed that the lesion was infiltrating further than the deep submucosal layer and it was therefore decided to treat the patient by laparoscopically assisted right hemicolectomy. The depressed lesion was found to be a well-differentiated adenocarcinoma invading the muscularis propria (diagnosed as IIc + IIa-like advanced adenocarcinoma). The surrounding flat elevated lesion was found to be hyperplastic mucosa. No adenomatous lesions were found. There have been few reported cases in which a preoperative diagnosis of carcinoma in a hyperplastic polyp has been made, but the possibility of carcinogenesis from hyperplastic polyps has come under consideration recently. This case was considered to be important because it raises the possibility that nonpolypoid cancer can develop from a hyperplastic polyp.

Reinvestigation of the requirement of cytosolic ATP for mitochondrial protein import

Protein import into mitochondria requires the energy of ATP hydrolysis inside and/or outside mitochondria. Although the role of ATP in the mitochondrial matrix in mitochondrial protein import has been extensively studied, the role of ATP outside mitochondria (external ATP) remains only poorly characterized. Here we developed a protocol for depletion of external ATP without significantly reducing the import competence of precursor proteins synthesized in vitro with reticulocyte lysate. We tested the effects of external ATP on the import of various precursor proteins into isolated yeast mitochondria. We found that external ATP is required for maintenance of the import competence of mitochondrial precursor proteins but that, once they bind to mitochondria, the subsequent translocation of presequence-containing proteins, but not the ADP/ATP carrier, proceeds independently of external ATP. Because depletion of cytosolic Hsp70 led to a decrease in the import competence of mitochondrial precursor proteins, external ATP is likely utilized by cytosolic Hsp70. In contrast, the ADP/ATP carrier requires external ATP for efficient import into mitochondria even after binding to mitochondria, a situation that is only partly attributed to cytosolic Hsp70.

Tom40 protein import channel binds to non-native proteins and prevents their aggregation

Mitochondria contain the translocator of the outer mitochondrial membrane (TOM) for protein entry into the organelle, and its subunit Tom40 forms a protein-conducting channel. Here we report the role of Tom40 in protein translocation across the membrane. The site-specific photocrosslinking experiment revealed that translocating unfolded or loosely folded precursor segments of up to 90 residues can be associated with Tom40. Purified Tom40 bound to non-native proteins and suppressed their aggregation when they are prone to aggregate. A denatured protein bound to the Tom40 channel blocked the protein import into mitochondria. These results indicate that, in contrast to the nonstick tunnel of the ribosome for polypeptide exit, the Tom40 channel offers an optimized environment to translocating non-native precursor proteins by preventing their aggregation.

Accuracy of radiographic assessment for the diagnosis of invasion depth in small invasive colorectal cancer

Radiographic findings of 113 submucosally invasive colorectal cancers (CRCs) <or=20 mm were investigated by two observers to examine whether barium radiography is predictive of the invasion depth in small colorectal cancer. Smooth surface, central barium fleck, fold convergency and eccentric rigidity were chosen as the radiographic determinants. Predictive values of the determinants for deep submucosal invasion were compared between 45 CRCs <or=10 mm and 68 CRCs >10 mm. 47 CRCs had invaded the submucosa superficially while 66 CRCs had invaded deeply. The concordance rate in the assessment of radiology was 90.3% in smooth surface, 92.9% in central barium fleck, 90.3% in fold convergency and 79.6% in eccentric rigidity. Positive predictive value of central barium fleck for deep submucosal invasion was significantly higher in CRCs>10 mm than in those <or=10 mm (0.86 vs. 0.64, p=0.034). In contrast, negative predictive values of smooth surface (0.89 vs. 0.34, p<0.00001), central barium fleck (0.87 vs. 0.38, p=0.0002), fold convergency (0.64 vs. 0.33, p=0.0023) and eccentric rigidity (0.79 vs. 0.48, p=0.023) were significantly higher in CRCs <or=10 mm than in those >10 mm. These findings suggest that barium radiography is a procedure which can give useful information in prediction of invasion depth in CRCs <or=10 mm in size.

Functional cooperation and separation of translocators in protein import into mitochondria, the double-membrane bounded organelles

Nearly all mitochondrial proteins are synthesized in the cytosol and subsequently imported into mitochondria with the aid of translocators: the TOM complex in the outer membrane, and the TIM23 and TIM22 complexes in the inner membrane. The TOM complex and the TIM complexes cooperate to achieve efficient transport of proteins to the matrix or into the inner membrane and several components, including Tom22, Tim23, Tim50 and small Tim proteins, mediate functional coupling of the two translocator systems. The TOM complex can be disconnected from the TIM systems and their energy sources (ATP and DeltaPsi), however, using alternative mechanisms to achieve vectorial protein translocation across the outer membrane

CCR4 is an up-regulated chemokine receptor of peripheral blood memory CD4+ T cells in Crohn's disease

Several chemokine receptors are expressed selectively on the surface of T cells depending on their polarization. The aim of this study was to characterize chemokine receptor expression in peripheral blood memory T cells in Crohn's disease (CD) and ulcerative colitis (UC), and to correlate the expression with disease activity. Peripheral blood mononuclear cells (PBMCs) were obtained from 24 patients with CD, 30 patients with UC, 24 normal controls and 10 disease controls. PBMCs were stained by anti-CCR3, CCR4, CCR5, CXCR3, CD4, CD8, CD45RO and beta 7 integrin, and the expression of the chemokine receptors were determined by flow cytometry. CCR4 expression on memory T cells was significantly lower in UC than in CD or normal controls, and that of memory CD4+ T and beta 7(high) memory CD4+ T cells was significantly higher in CD than in UC or normal controls. CCR4 expression on memory CD4+ T cells exhibited significant positive correlation with disease activity in CD, and this decreased significantly after treatment. Such a decrease was not found in the disease controls. CCR5 and CXCR3 expression on memory CD8+ T cells was significantly lower in CD than in normal controls. CXCR3 expression on beta 7(high) memory CD4+ T and CXCR3 expression on memory CD8+ T cells were lower in UC than in normal controls. These findings suggest that in peripheral blood memory T cells, chemokine receptor expression is different between CD and UC. Enhancement of CCR4 and suppression of CCR5 and CXCR3 seem to be the characteristic chemokine receptor profile in peripheral blood memory T cells of CD.

A case of multicentric gastric carcinoids without hypergastrinemia

We have encountered an unusual case of gastric carcinoid tumors. Gastroscopic examination of a 71-year-old male patient showed eight smooth protrusions at the greater curvature of the gastric body, some of which had central depressions. Endoscopic ultrasonography demonstrated that the largest tumor (2.6 cm in diameter) was located in the submucosal layer. The patient had a normal serum gastrin level and was negative for antiparietal cell antibody. The patient was also found to have a pituitary tumor, an adenomatous goiter, and bilateral Warthin's tumors of the parotid glands. Histological examination of the resected stomach identified 12 discrete carcinoid tumors. There was no evidence of atrophic gastritis or of endocrine cell micronests. No mutations of the MEN1 gene were found on genomic DNA analysis. Despite the multiplicity of carcinoid tumors, we diagnosed type 3 gastric carcinoid in this patient.

Is endoscopic ultrasonography indispensable in assessing the appropriateness of endoscopic resection for gastric cancer?

BACKGROUND AND STUDY AIMS

Endoscopic resection is increasingly being used in the treatment of early gastric cancer. The aim of the present study was to investigate the accuracy of pretherapeutic staging techniques for assessing the appropriateness of endoscopic resection.

PATIENTS AND METHODS

Both endoscopy and endosonography were carried out at our institution in the treatment of 234 early gastric cancers, with histological confirmation of malignancy following surgical resection (137 lesions) or endoscopic resection (97 lesions). The accuracy in detecting intramucosal cancer with each of the diagnostic procedures was assessed.

RESULTS

The accuracy rates for detecting intramucosal cancer using endoscopy and endosonography were calculated as 84 % (197 of 234) and 78 % (182 of 234), respectively. The accuracy tended to be lower in lesions located in the upper third of the stomach, in those measuring 2 cm or more in diameter, and in those with an undifferentiated histology with ulcer fibrosis. However, there were no significant differences in the accuracy rates between endoscopy and endosonography. Precise staging was achieved by endoscopy alone in 103 of 109 differentiated adenocarcinomas without ulcer fibrosis, where the lesions measured less than 2 cm in diameter.

CONCLUSIONS

Endoscopic resection is indicated in intramucosal gastric cancer lesions showing differentiated histology, no ulcer fibrosis and a diameter of less than 2 cm. EUS may additionally be used for further evaluation in these patients.

Endosonographic features of Brunner's gland hamartomas which were subsequently resected endoscopically

BACKGROUND AND STUDY AIMS

Brunner's gland hamartomas are uncommon duodenal submucosal tumors. We aim to describe their morphological characteristics, with particular attention to the endosonographic features.

PATIENTS AND METHODS

We reviewed the radiological, endoscopic, endosonographic, and histological findings from six Brunner's gland hamartomas which were completely removed by endoscopic resection.

RESULTS

The lesions appeared as broad-based, sessile, or pedunculated submucosal tumors, measuring 0.7 to 2 cm in maximal diameter. Three lesions contained tiny dimple-like depressions on the surface; in one lesion these were only recognized following the use of an endoscopic dye-spraying technique. All the lesions could be safely removed by endoscopic resection after endosonographic confirmation of the layer origin within the submucosa. The internal echo structure of the tumors appeared to be solid echogenic in two, simple cystic in two, and multicystic in the remaining two lesions. In three lesions with an indistinct boundary, some stromal proliferation and solid Brunner's glands were recognized in an area extending from the mucosa to the submucosa. These endosonographic features corresponded to histological findings comprising stromal proliferation and various degrees of solid and cystic glandular Brunner's glands.

CONCLUSIONS

Brunner's gland hamartoma is characterized endosonographically by a heterogeneous solid and/or cystic mass within the submucosa.

Tim50 is a subunit of the TIM23 complex that links protein translocation across the outer and inner mitochondrial membranes

Based on the results of site-specific photocrosslinking of translocation intermediates, we have identified Tim50, a component of the yeast TIM23 import machinery, which mediates translocation of presequence-containing proteins across the mitochondrial inner membrane. Tim50 is anchored to the inner mitochondrial membrane, exposing the C-terminal domain to the intermembrane space. Tim50 interacts with the N-terminal intermembrane space domain of Tim23. Functional defects of Tim50 either by depletion of the protein or addition of anti-Tim50 antibodies block the protein translocation across the inner membrane. A translocation intermediate accumulated at the TOM complex is crosslinked to Tim50. We suggest that Tim50, in cooperation with Tim23, facilitates transfer of the translocating protein from the TOM complex to the TIM23 complex

Subcellular localization of PP5/TFPI-2 in human placenta: a possible role of PP5/TFPI-2 as an anti-coagulant on the surface of syncytiotrophoblasts

Placental protein 5 (PP5)/tissue factor pathway inhibitor-2 (TFPI-2), a serine proteinase inhibitor, is homologous to tissue factor pathway inhibitor (TFPI) and commonly found in peripheral blood of pregnant woman. Although TFPI is well known to be synthesized primarily in endothelium and to play an important role in regulation of the extrinsic pathway of blood coagulation, the function of PP5/TFPI-2 remains unclear. Our previous report demonstrated that PP5/TFPI-2 expression is ubiquitous and extremely high in growing placental tissue. Using newly generated polyclonal anti-PP5/TFPI-2 antibody, and by immunohistochemistry and immunoelectromicroscopy, we examined precise localization of PP5/TFPI-2 in placenta especially in syncytiotrophoblasts, which had been shown to produce PP5/TFPI-2 mRNA by our previous study using in situ hybridization. Immunoelectromicroscopy revealed PP5/TFPI-2 localizing on the surface of the microvilli and the membrane of endoplasmic reticulum of syncytiotrophoblasts. To confirm the cell surface association of PP5/TFPI-2, placental villi were incubated with heparin and resultant soluble fraction was analysed by Western blotting. Heparin liberating PP5/TFPI-2 from villi suggested that PP5/TFPI-2 might be retained on the microvilli surface through the binding to membrane-anchored proteoglycans such as glypican and/or syndecan family members. We also examined the relationship between the presence of cell layer of syncytiotrophoblasts and the coagulation using clinical specimens, and revealed that the fibrin depositions were specifically observed on the regions lacking syncytiotrophoblasts cell layer in placental villi. Therefore, it is likely that during pregnancy PP5/TFPI-2 may be retained on the surface of placental villi via proteoglycans, and may play an important role to maintain intervillous blood flow and the patency of microvasculature in feto-maternal blood system mediated by the inhibition of serine proteinases involved in the blood coagulation.

Sciatic nerve regeneration in rats induced by transplantation of in vitro differentiated bone-marrow stromal cells

Bone marrow stromal cells (MSCs) are multipotent stem cells that have the potential to differentiate into bone, cartilage, fat and muscle. We now demonstrate that MSCs can be induced to differentiate into cells with Schwann cell characteristics, capable of eliciting peripheral nervous system regeneration in adult rats. MSCs treated with beta-mercaptoethanol followed by retinoic acid and cultured in the presence of forskolin, basic-FGF, PDGF and heregulin, changed morphologically into cells resembling primary cultured Schwann cells and expressing p75, S-100, GFAP and O4. The MSCs were genetically engineered by transduction with retrovirus encoding green fluorescent protein (GFP), and then differentiated by treatment with factors described above. They were transplanted into the cut ends of sciatic nerves, which then responded with vigorous nerve fibre regeneration within 3 weeks of the operation. Myelination of regenerated fibers by GFP-expressing MSCs was recognized using confocal and immunoelectron microscopy. The results suggest that MSCs are able to differentiate into myelinating cells, capable of supporting nerve fibre re-growth, and they can therefore be applied to induce nerve regeneration.

Binding properties of Bacillus thuringiensis Cry4A toxin to the apical microvilli of larval midgut of Culex pipiens

Cry4A is a dipteran-specific delta-endotoxin produced by Bacillus thuringiensis, and toxic to Culex pipiens (mosquito) larvae. The immunohistochemical staining of the midgut sections of C. pipiens larvae revealed that Cry4A bound in vitro and in vivo to the microvilli of the epithelial cells of posterior midgut and gastric caecae. The binding of digoxigenin-labeled Cry4A (DIG-Cry4A) to the apical microvilli was almost abolished in the presence of excess unlabeled Cry4A, suggesting that the binding of Cry4A to the microvilli was specific. Several Cry4A-specific binding proteins were detected using the ligand blotting technique with DIG-Cry4A. Moreover, an insertion assay was done, where the binding of DIG-Cry4A to the BBMVs was completely irreversible and did not compete with excess unlabeled Cry4A. On the basis of these results, we propose a schematic interpretation for the binding process of Cry4A.

Effect of psychological stress on human growth hormone response to thyrotropin-releasing hormone in normal controls

Human growth hormone (hGH) responses to thyrotropin-releasing hormone (TRH) were investigated in normal subjects under psychological stress. Fifteen subjects (4 men and 11 women), whose ages ranged from 19 to 22 years, were studied. The mirror-drawing test (MDT) was performed to induce psychological stress. Plasma hGH and prolactin (PRL) were determined serially before, during and after the following tests: TRH alone (500 micrograms synthetic TRH i.v. bolus), MDT alone, and TRH with MDT. The changes in hGH concentrations with MDT alone were not significant. The hGH response to TRH alone also showed no remarkable change; however, hGH responses to TRH combined with MDT were significantly higher than the responses to TRH alone. PRL did not respond with MDT alone but responded significantly with the other two tests. Thus there was a divergence in hGH and PRL secretion to TRH and psychological stress. Significant increases in hGH secretion were observed only when TRH and psychological stress were combined as stimuli.

Cap polyposis of the colon and rectum: an analysis of endoscopic findings

BACKGROUND AND STUDY AIMS

Because of the rarity of cap polyposis of the colon and rectum, the endoscopic features of this condition have not been specified to date. The aim of this study is to characterize the endoscopic features of cap polyposis.

PATIENTS AND METHODS

The diagnosis of cap polyposis was established by histologic findings in specimens obtained endoscopically or surgically from four patients. Colonoscopic findings in the four patients were retrospectively reviewed.

RESULTS

The endoscopic features were divided into semipedunculated type (three patients) and flat-topped protruding type (one patient). In the semipedunculated type, the polyps were characterized by reddish protrusions of various configurations with eroded surface in the rectosigmoid colon. In the remaining patient, all the lesions were flat protrusions with a reddish central depression. The polyps of both types became smaller in size and fewer in number at the proximal part of the sigmoid colon. Multiple white specks were observed in the intervening mucosa in all four patients.

CONCLUSIONS

The prominence of the polyps at the distal part of the colon and rectum and multiple white specks in the intervening mucosa seem to be the additional endoscopic features suggestive of cap polyposis.

Cystic submucosal tumors in the gastrointestinal tract: endosonographic findings and endoscopic removal

BACKGROUND AND STUDY AIMS

The aim of the present study was to describe the endosonographic findings in gastrointestinal cystic submucosal tumors.

PATIENTS AND METHODS

The endosonographic and clinicopathological findings in 51 patients with a confirmed diagnosis of cystic submucosal tumors were reviewed.

RESULTS

Endosonographically, cystic submucosal tumors were classified into simple cystic, multicystic, and solid cystic tumor types. The simple cystic tumor type was frequently identified in cysts, and rarely in Brunner's gland hamartomas or in heterotopic gastric mucosa. The multicystic tumor type was common in lymphangiomas, followed by gastric cystic malformations, hemangiomas, and Brunner's gland hamartomas. The solid cystic tumor type included duplication cysts, heterotopic gastric mucosa, heterotopic pancreas, myogenic tumors with advanced cystic degeneration, and gastric tuberculomas. Based on the endosonographic findings, 14 lesions were safely treated with endoscopic removal, using in particular the unroofing technique (cutting off the upper part of the tumors) in nine lesions.

CONCLUSIONS

Endosonography is a useful diagnostic modality for investigating cystic submucosal tumors.

A practical technique to postfix nanogold-immunolabeled specimens with osmium and to embed them in Epon for electron microscopy

Nanogold is a tiny gold probe, freely diffusible in cells and tissues, and is suitable for pre-embedding immunohistochemistry. However, it is necessary to develop Nanogold to a larger size so that it can be observed by conventional transmission electron microscopy. Silver enhancement is usually used for visualizing Nanogold, but the silver shell produced is unstable in OsO(4) and often becomes invisible after OsO(4) postfixation, which is necessary for good visualization of ultrastructure. We used silver enhancement with silver acetate, followed by gold toning with chloroauric acid, to replace the silver shell with a more stable gold in order to observe Nanogold after osmium fixation and Epon embedding. This technique is applicable to various intra- and extracellular antigens. For correlative observation of immunolabled specimens by light and electron microscopy, specimens adhered to slideglasses were embedded in Epon under non-adhesive plastic film. By heating the Epon sheets after polymerization, these supports were removed without difficulty and provided easy correlative observation.

Two distinct mechanisms drive protein translocation across the mitochondrial outer membrane in the late step of the cytochrome b(2) import pathway

The import of cytochrome b(2) into mitochondria consists of two steps. The translocation of the first part of the presequence across the inner membrane is coupled with the translocation of the tightly folded heme-binding domain across the outer membrane and requires a membrane potential DeltaPsi and the functions of mitochondrial Hsp70 (mHsp70) in the matrix. Once the heme-binding domain has passed the outer membrane, the translocation of the rest of the polypeptide chain across the outer membrane becomes independent of DeltaPsi and mHsp70. Here we analyzed the late DeltaPsi- and mHsp70-independent step in the transport of cytochrome b(2) fusion proteins into the intermembrane space (IMS). The import of the cytochrome b(2) fusion proteins containing two protein domains linked by a spacer segment into mitochondria was arrested at a stage at which one domain folded on each side of the outer membrane, along the pathway that is consistent with the stop-transfer model. The mature-size form of the translocation intermediate could move across the outer membrane in both directions, and the stabilization of the protein domain in the IMS promoted the forward translocation. On the other hand, the intermediate-size form of the translocation intermediate, which retains the anchorage to the inner membrane, was transported into the IMS independently of the stability of the protein domain in the IMS. These results suggest that two distinct mechanisms, the Brownian ratchet and the anchor diffusion mechanisms, can operate for the transmembrane movement of the mature-size form and the intermediate-size form, respectively, of cytochrome b(2) species.

Activation process of dipteran-specific insecticidal protein produced by Bacillus thuringiensis subsp. israelensis

Dipteran-specific insecticidal protein Cry4A is produced as a protoxin of 130 kDa in Bacillus thuringiensis subsp. israelensis. Here we performed the in vitro processing of Cry4A and showed that the 130-kDa protoxin of Cry4A was processed into the two protease-resistant fragments of 20 and 45 kDa through the intramolecular cleavage of a 60-kDa intermediate. The processing into these two fragments was also observed in vivo. To investigate functional properties of the two fragments, GST (glutathione S-transferase) fusion proteins of the 60-kDa intermediate and the 20- and 45-kDa fragments were constructed. Neither the GST-20-kDa fusion protein (GST-20) nor the GST-45-kDa fusion protein (GST-45) was actively toxic against mosquito larvae of Culex pipiens, whereas the GST-60-kDa intermediate fusion protein (GST-60) exhibited significant toxicity. However, when the two fusion proteins GST-20 and GST-45 coexisted, significant toxicity was observed. The coprecipitation experiment demonstrated that the two fragments associated with each other. Therefore, it is strongly suggested that the two fragments formed an active complex of apparently 60 kDa. A mutant of the 60-kDa protein which was apparently resistant to the intramolecular cleavage with the midgut extract of C. pipiens larvae had toxicity slightly lower than that of GST-60.

Polymorphism of heat-shock protein gene HSP70-2 in Crohn disease: possible genetic marker for two forms of Crohn disease

BACKGROUND

Previous reports have shown that heat-shock protein 70 (HSP70) may be associated with Crohn disease. However, genetic analysis of the HSP70 gene in Crohn disease has not been done. The aim of this study is to investigate whether HSP70-2 gene polymorphism is involved in susceptibility to Crohn disease in the Japanese population and whether it correlates with clinical manifestation of the disease.

METHODS

A total of 108 genetically unrelated patients with Crohn disease and 108 healthy controls were typed for HSP70-2 PstI polymorphism by restriction fragment length polymorphism analysis (alleles A and B). Patients with Crohn disease were classified into two types: either perforating or non-perforating.

RESULTS

Genotype and allele frequency did not differ between patients and controls. In patients with Crohn disease, allele A frequency was significantly higher in the non-perforating than in the perforating type (P = 0.02). When patients with Crohn disease of more than 6.7 years' duration were assessed, the differences in genotype and allele frequency between the two groups became more significant (P < 0.001 and P < 0.001, respectively).

CONCLUSIONS

These data suggest that HSP70-2 gene polymorphic allele A is a possible genetic marker of less severe clinical phenotype in Japanese patients with Crohn disease.

Local drug delivery system using ceramics: vacuum method for impregnating a chemotherapeutic agent into a porous hydroxyapatite block

We performed an experimental study on a new drug delivery system that employs a porous hydroxyapatite block (HAb) (composition: Ca10(PO4)6(OH)2)) to conduct sustained release of a chemotherapeutic agent. To confirm penetration of the agent into the HAb (2 cm3), an aqueous solution containing eosin dye was used at various vacuum pressures. To estimate the storage capacity of the HAb, blocks were weighed before and after being impregnated with the aqueous dye solutions, and the capacity of the block was calculated from the increase in weight after vacuum. In this slow-release study using vacuum, the anti-cancer drug methotrexate (MTX) was used in vitro. Four HAb (1 cm3) containing different concentrations of MTX, ranging from 1.22 to 2.38 mg per block, were studied. All were found to release the drug, maintaining a mean concentration of 0.22 to 0.32 microg/ml even after twelve days. This concentration is high enough to be effective against tumor cells. The results suggest that HAb impregnated with a chemotherapeutic agent using a simple vacuum system may serve as a valuable new method of administering local chemotherapy, primarily when used as a strut graft for bone defects. This new drug delivery system can also be used as an adjuvant material in extended curettage, which can also discourage recurrence of benign tumors without any risk of systemic toxicity.

[An autopsy case of elderly idiopathic enlargement of the right atrium]

We report an autopsy case of an 88-year-old man with idiopathic enlargement of the right atrium which is considered to be the oldest case reported. The patient was given a diagnosis of atrial fibrillation at the age of 75 years, when he developed congestive heart failure. Bradycardia associated with partial atrial standstill was detected and, the patient underwent implantation of a pacemaker at age 77. An echocardiogram revealed marked enlargement of the right atrium and moderate enlargement of the left atrium. Thus, idiopathic enlargement of the right atrium was diagnosed. He had recurrent congestive heart failure before admission to our hospital because of malnutrition and anemia. Although he was treated with high calorie intravenous infusion and blood transfusion, he died of pneumonia and heart failure. Postmortem examination revealed that the heart weighed 430 g, and there was marked dilatation of the right atrium which had an extremely thin wall. The annular circumference of the tricuspid valve was markedly dilated, 170 mm, resulting in tricuspid regurgitation. The left atrium was moderately dilated and the right and left ventricles were slightly dilated. Histologically, the free wall of the right atrium was totally replaced by fibrous tissue and atrioventricular valves did not reveal any rheumatic changes. These pathological findings were compatible with idiopathic enlargement of the right atrium. There has been no previous case report of idiopathic enlargement of the right atrium in a patient aged 80 years of age or over.

Regression of carotid wall thickening after corticosteroid therapy in Takayasu's arteritis evaluated by B-mode ultrasonography: report of 2 cases

We describe 2 young Japanese female patients with active Takayasu's arteritis whose diagnosis was mainly based on the characteristic ultrasonographic finding, that is, a circumferential vascular wall thickening in common carotid arteries. Following corticosteroid therapy, serial ultrasonographic examination documented the improvement of their thickened carotid walls (in Case 1 from 1.4 to 0.5 mm after 2 months of therapy, in Case 2 from 1.5 to 0.9 mm after 9 months of therapy). These cases emphasize that ultrasonography is useful for evaluation of the therapeutic effect as well as for the diagnosis of Takayasu's arteritis in its early stage.

Primary cardiac leiomyosarcoma growing rapidly and causing right ventricular outflow obstruction

Leiomyosarcomas are extremely rare primary cardiac tumors. We report a rapidly growing primary leiomyosarcoma of the right ventricle, which obstructed the right ventricular outflow tract within one month after symptom onset in a 68-year-old man. Two-dimensional echocardiography was useful in diagnosing the extent and progression of the tumor. The tumor was surgically resected on an emergency basis, and the right ventricle and pulmonary artery were successfully reconstructed. Recurrence of the tumor on the right ventricle was observed, and the patient was overcome by sudden dyspnea and died three months after surgery.

Immunocytochemistry of extracellular matrix components in the rat seminiferous tubule: electron microscopic localization with improved methodology

BACKGROUND

Cell-cell interactions between Sertoli, myoid, Leydig, and germ cells are thought to be essential for spermatogenesis. These cells interact with each other through the extracellular matrices (ECMs) of the testicular lamina propria, which thus may have an important function in spermatogenesis. For an understanding of the role of ECMs in spermatogenesis, it is important to investigate the molecular constitution of the testicular ECM. We examined the distribution of type IV, V, and VI collagens (Cols), laminin (LM), fibronectin (FN), and heparan sulfate proteoglycan (HSPG) in the rat testicular lamina propria.

METHODS

Adult rat testes were fixed with 4% paraformaldehyde and 0.2% glutaraldehyde. Ultrathin frozen sections were made and immunolabeling was performed according to the method of Tokuyasu (1986 J. Microsc., 143:139-149). Alternatively, for preembedding immunocytochemistry, we used labeling with nanogold, followed by silver enhancement and gold toning. The tissues were then fixed with osmium and embedded in Epon (Sawada and Esaki 1994 J. Electron Microsc., 43:361-366). These specimens were examined in a JEOL JEM-100C transmission electron microscope operated at 80 kV.

RESULTS

Col IV, LM, and HSPG were localized in the basement membranes of the seminiferous tubule (ST-BM) and in the BM of myoid cells. Cols V and VI, and FN were localized both in the connective tissue between the seminiferous tubule and the myoid cells (tubule-myoid connective tissue) and in the connective tissue between the myoid cells and the lymphatic endothelial cells (myoid-endothelium connective tissue). Furthermore, statistical analysis of the micrographs of immunogold labeling for Col IV, LM, and FN around the ST-BM suggested that the Col IV molecule is located uniformly in the ST-BM, whereas the LM molecule is distributed mainly in the lamina rara of ST-BM, and the FN molecule appears to be present predominantly in the tubule-myoid connective tissue.

CONCLUSIONS

Distinct distribution patterns were observed for each antigen within the testicular lamina propria at the ultrastructural level. However, localization of some components was not consistent with localizations reported by others.

Use of nanogold followed by silver enhancement and gold toning for preembedding immunolocalization in osmium-fixed, Epon-embedded tissues

A reliable, sensitive, high-resolution method with good structural visualization for preembedding immunoelectron microscopy was proposed. The present technique involves the following processes. Immunolabeling of cryostat sections with primary antibodies and with nanogolds, silver intensification for visualization of nanogold secondary antibodies, gold-toning for stabilization of silver shells, and osmium postfixation and embedding in Epon for good structural visualization. The technique was applied to rat testis with anti-laminin and anti-fibronectin antibodies, showing that these two proteins are localized differentially in the lamina propria of the tissue.

[Management of short bowel syndrome in infants--experience of adjunctive surgical therapy in three cases]

During the past nine years period, we managed 7 cases with short bowel syndrome resulting from massive intestinal resection in the neonatal period. Six children, aged 2 to 8 years are alive, and one died from cardiomyopathy caused by selenium deficiency at the age of one year. The carbohydrate-free milk was used for initial enteral nutrition, and the result was encouraging in 4 cases. In 3 cases in which residual small bowel varied between 6.5 to 18 cm, the enteral feeding was not incapable. These cases underwent adjunctive surgical therapy. Tailoring jejunoplasty was performed in the first case, and bowel lengthening in the second case. In both cases enteral nutrition was advanced postoperatively. The third patient who had rapid intestinal transit time underwent isoperistaltic colon interposition. Intestinal transit time was increased and enteral nutrition was advanced gradually.