Malignant gastroduodenal obstructions: treatment by means of a covered expandable metallic stent-initial experience

PURPOSE

To investigate the technical feasibility and clinical effectiveness of a polyurethane-covered expandable nitinol stent in the treatment of malignant gastroduodenal obstructions.

MATERIALS AND METHODS

The stent was constructed in-house by weaving a single thread of 0.2-mm nitinol wire in a tubular configuration and was covered with polyurethane solution by means of a dipping method. With fluoroscopic guidance, the stent was placed in 19 consecutive patients with malignant gastric outlet obstruction (n = 15) or duodenal obstruction (n = 4). All patients had severe nausea and recurrent vomiting, and their obstructions were inoperable.

RESULTS

Stent placement was technically successful in all but one patient. After stent placement, symptoms improved in all but one patient, who had another stenosis at the proximal jejunum. One patient with stent placement in the second portion of the duodenum became jaundiced. During the mean follow-up of 11 weeks, stent migration occurred in five patients 1-4 days after the procedure. All patients with stent migration were treated by means of placing a second, uncovered nitinol stent. Two of these five patients showed recurrence of stricture because of tumor ingrowth; they underwent coaxial placement of a third, covered nitinol stent with good results.

CONCLUSION

Placement of a polyurethane-covered expandable nitinol stent seems to be technically feasible and effective for palliative treatment of inoperable malignant gastroduodenal obstructions. Stent migration, however, is problematic and requires further investigation.

Central administration of an antisense oligodeoxynucleotide against type I pituitary adenylate cyclase-activating polypeptide receptor suppresses synthetic activities of LHRH-LH axis during the pubertal process

Central administration of an antisense oligodeoxynucleotide against type I pituitary adenylate cyclase-activating polypeptide receptor suppresses synthetic activities of LHRH-LH axis during the pubertal process In the present study, we determined the expression of pituitary adenylate cyclase-activating polypeptide (PACAP) and PACAP receptor type I (PAC1) genes during juvenile development and the pubertal process. Female rats were assigned--based on uterine weights, the presence and abundance of uterine fluid, and their vaginal patency--to one of the following: anestrus (AE), early proestrus (EP), late proestrus (LP) or first estrus (E). The hypothalami from 22-, 24- and 26-day-old animals and from those in the peripubertal phases of AE, EP, LP and E were collected, and the content of PACAP and PAC1 mRNA was assessed. These levels were found to decrease in EP and LP. To determine the effect of PACAP on prepubertal luteinizing hormone-releasing hormone (LHRH) and LH synthesis through PAC1, a PAC1 antisense oligodeoxynucleotide (ODN) was i.c.v.-administered, and mRNA levels of LHRH, LH beta, and LHRH receptor (LHRH-R) were determined. Prepubertal increases in LHRH, LH beta, and LHRH-R mRNA levels were markedly suppressed, and the onset of puberty was delayed by the i.c.v. injection of the antisense PAC1 ODN. These data suggest that PACAP may play a role in the regulation of hypothalamic LHRH neurons, through which it regulates synthetic machinery of pituitary LH, during the pubertal process.

Involvement of two NF-kappa B binding elements in tumor necrosis factor alpha -, CD40-, and epstein-barr virus latent membrane protein 1-mediated induction of the cellular inhibitor of apoptosis protein 2 gene

The antiapoptotic function of NF-kappaB is believed to be mediated through the induction of antiapoptotic genes. Among the antiapoptotic genes, cellular inhibitor of apoptosis protein 2 (c-IAP2/HIAP-1/MIHC) is originally identified as a molecule recruited to the tumor necrosis factor (TNF) receptor complex, and its expression is preferentially up-regulated by TNF and other stimuli activating NF-kappaB. However, direct evidence of transcriptional regulation of NF-kappaB on the c-IAP2 gene is still missing. Here, we have cloned and characterized the promoter region required for NF-kappaB-dependent transcription of the c-IAP2 gene. Sequencing of a 3.5-kilobase fragment of the 5'-flanking region of the c-IAP2 gene has identified a TATA-like sequence and potential binding sites for nuclear factor of activated T cells, interferon regulatory factor 1, activator protein 1, glucocorticoid response element, and three putative NF-kappaB binding elements. Deletion and mutational analysis of the 5'-flanking region linked to the luciferase gene revealed that transcriptional activation by TNF or interleukin 1 is mediated cooperatively by two NF-kappaB binding sites. Electrophoretic mobility shift assays characterized that the two NF-kappaB sites can be recognized and bound by the NF-kappaB p50/p65 heterodimer. In addition, the transcription of c-IAP2 promoter was strongly up-regulated when CD40 or Epstein-Barr virus latent membrane protein 1 was overexpressed.

New beta -lactamase inhibitory protein (BLIP-I) from Streptomyces exfoliatus SMF19 and its roles on the morphological differentiation

A new beta-lactamase inhibitory protein (BLIP-I) from Streptomyces exfoliatus SMF19 was purified and characterized. The molecular mass of BLIP-I was estimated to be 17.5 kDa by gel filtration fast protein liquid chromatography. The N-terminal sequence was NH(2)-Asn-Ser-Gly-Phe-Ser-Ala-Glu-Lys-Tyr-Glu-Gln-Ile-Gln-Phe-Gly. BLIP-I inhibited Bacto(R) Penase (Difco), and plasmid encoded TEM-1 beta-lactamase, whereas it did not inhibit Enterobacter cloacae beta-lactamases. The K(i) value of BLIP-I against TEM-1 beta-lactamase was determined to be 0.047 nm. The gene (bliA) encoding BLIP-I protein was identified by screening a genomic library using an oligonucleotide probe with a sequence based on the N-terminal sequence of BLIP-I. Analysis of the nucleotide sequence revealed that the gene was 558 base pairs in length and encoded a mature protein of 157 amino acid residues preceded by a 29-amino acid signal sequence. Pairwise comparison of the deduced amino acid sequence showed 38% identity with BLIP of Streptomyces clavuligerus. Furthermore, the 49th amino acid residue of BLIP-I was identical to Asp-49 of BLIP that was characterized to be an important residue for the inhibitory activity of BLIP. A modified BLIP-I in which Asp-49 was replaced by alanine (D49A) was obtained by site-directed mutagenesis. The inhibitory activities of recombinant (r) BLIP-I and its D49A mutant derivative, expressed in Escherichia coli, were compared. The K(i) value of rBLIP-I against TEM-1 beta-lactamase was similar to that of wild-type BLIP-I, but the D49A mutation increased the K(i) of rBLIP-I inhibition approximately 200-fold. A disruption mutant of the bliA gene in S. exfoliatus SMF19 was obtained by replacing the wild-type bliA gene with a copy inactivated by inserting a hygromycin resistance gene. The disruption mutant showed a bald phenotype, indicating that the bliA gene plays a role in morphological differentiation.

Use of a lacrimal stent retrieval hook in the removal of occluded plastic and expandable metallic lacrimal stents

PURPOSE

To evaluate the clinical usefulness of a stent retrieval hook in the removal of occluded lacrimal stents.

MATERIALS AND METHODS

The hook consisted of an inner hook part and an outer pusher part. Under administration of local anesthetic, the retrieval hook was introduced into the nasal cavity and aimed laterally toward the inferior meatus to grasp the distal end of the stent. After grasping the end of the stent, the sheath was pushed to fully grasp it. After that, the hook was pulled out of the external naris. The retrieval hook was used to remove 267 occluded lacrimal plastic or metallic stents.

RESULTS

Technical success rate was 97% in the removal of plastic stents and 96% in the removal of metallic stents. The causes of technical failure were entrenchment of granulation tissue into the stent in six plastic stents and one metallic stent, and inaccessibility of the hook to the distal tip of the stent in one plastic stent. These eight stents were removed by an otorhinolaryngologist or an ophthalmologist. Epistaxis occurred in six patients, which was controlled by a nasal pack.

CONCLUSIONS

The lacrimal stent retrieval hook seems useful for the removal of occluded stents.

Effects of dopamine and melatonin on the regulation of the PIT-1 isotype, placental growth hormone and lactogen gene expressions in the rat placenta

Rat placenta produces several members of the placental prolactin-growth hormone (PRL-GH), including placental lactogen (PL) and placental prolactin like protein (PLP), during pregnancy. It is important to study placental local regulators that control the expression of PRL-GH genes. We have previously reported that dopamine (DA) can regulate Pit-1 and PL-II gene expressions. In this study we aimed to investigate the local expression of melatonin receptor 1a (Mel1a) and the effects of DA and melatonin on the expressions of PL-Iv, PL-II, PLP-C genes and Pit-1 gene that are involved in the expression of PRL-GH genes in the rat pituitary and placenta. According to the Northern blot analysis, DA receptor 2 (D2) was expressed in the rat placenta. We also report on the local expression of Mel1a in the rat placenta for the first time. Injected DA agonist, bromocriptine (in vivo) decreased PL-Iv, PLP-C and Pit-1 mRNA levels in the rat placenta. The melatonin agonist, chloromelatonin in culture media also decreased the levels of PL-Iv, PL-II and PLP-C mRNA. However, melatonin does not affect the Pit-1 mRNA level. These data suggest that D2 and Mel1a may control the expression of PRL-GH genes in the rat placenta and its response to the extracellular changes of DA and melatonin secreted from the maternal organ. However, Pit-1 may not be involved in the Mel1a induced inhibition of PRL-GH gene expressions in the rat placenta.

Tracheobronchial strictures: treatment with a polyurethane-covered retrievable expandable nitinol stent--initial experience

A polyurethane-covered retrievable expandable stent was placed in 13 patients with tracheobronchial strictures. In four patients with benign strictures, the stent was removed with use of a retrieval hook 2-6 months after placement. After stent removal, three of the four patients did not need further treatment. The retrievable stent warrants further investigation in the treatment of tracheobronchial strictures.

Experimental preretinal neovascularization by laser-induced thrombosis in albino rats

The primary objective of this study was to develop a simple experimental model of angiogenesis by photodynamic thrombosis of the retinal veins in Sprague-Dawley rats. After a tail vein injection of rose bengal (40 mg/kg), all major retinal veins adjacent to the optic nerve head were photocoagulated with an argon green laser. The eyes were examined regularly for the following eight weeks. A grading system was devised using fluorescein angiograms and ADPase staining to describe the progression of the new vessels. Nine out of ten eyes showed development of the preretinal new vessels by day 14. Seven weeks after laser coagulation, 2 of 5 eyes developed localized tractional retinal detachment. Regression of the neovascularization was not noted in any of the animals during the follow-up period. The authors were able to establish an experimental model for preretinal neovascularization by vein occlusion. This model may be applied in study of the pathogenesis and treatment of retinal neovascularization.

Assessment of metal pollution in Onsan Bay, Korea using Asian periwinkle Littorina brevicula as a biomonitor

Cadmium (Cd), lead (Pb), copper (Cu) and zinc (Zn) concentrations in the marine gastropod, Littorina brevicula Philippi, were determined to assess the metal pollution in Onsan Bay, Korea. Samples of L. brevicula employed as a biomonitor and seawater were collected from 12 to 20 stations of Onsan Bay in November 1997, respectively. Dissolved metal concentrations in surface seawater were highest at the station near Onsan Non-ferrous Industrial Complex: 1.15 micrograms l-1 for Cd, 2.49 micrograms l-1 for Pb, 3.75 micrograms l-1 for Cu and 23.98 micrograms l-1 for Zn. These values were 1-2 orders higher than those shown at outer regions of the Bay. Metal concentrations in the soft body of periwinkles were highly variable at different sampling locations: 0.48-27.11 micrograms g-1 for Cd, 1.41-24.91 micrograms g-1 for Pb, 57-664 micrograms g-1 for Cu and 83-246 micrograms g-1 for Zn. The values from stations near the industrial complex were higher than those expected from relationships between body sizes and metal body burdens in periwinkles collected from the whole Korean coast. Spatial distribution of metal concentrations in the periwinkle and seawater indicated that Onsan industrial complex near the Bay is the input source of these metals. Especially, Cd and Pb concentrations in the periwinkle and seawater were distinctly decreased with distance from the Onsan industrial complex. Non-essential metals such as Cd and Pb in the periwinkle showed a strong correlation with dissolved metal concentrations in seawater. Conversely, essential Cu and Zn in the periwinkle were hardly explained by those in seawater, except at the most contaminated sites.

An Arabidopsis GSK3/shaggy-like gene that complements yeast salt stress-sensitive mutants is induced by NaCl and abscisic acid

GSK3/shaggy-like genes encode kinases that are involved in a variety of biological processes. By functional complementation of the yeast calcineurin mutant strain DHT22-1a with a NaCl stress-sensitive phenotype, we isolated the Arabidopsis cDNA AtGSK1, which encodes a GSK3/shaggy-like protein kinase. AtGSK1 rescued the yeast calcineurin mutant cells from the effects of high NaCl. Also, the AtGSK1 gene turned on the transcription of the NaCl stress-inducible PMR2A gene in the calcineurin mutant cells under NaCl stress. To further define the role of AtGSK1 in the yeast cells we introduced a deletion mutation at the MCK1 gene, a yeast homolog of GSK3, and examined the phenotype of the mutant. The mck1 mutant exhibited a NaCl stress-sensitive phenotype that was rescued by AtGSK1. Also, constitutive expression of MCK1 complemented the NaCl-sensitive phenotype of the calcineurin mutants. Therefore, these results suggest that Mck1p is involved in the NaCl stress signaling in yeast and that AtGSK1 may functionally replace Mck1p in the NaCl stress response in the calcineurin mutant. To investigate the biological function of AtGSK1 in Arabidopsis we examined the expression of AtGSK1. Northern-blot analysis revealed that the expression is differentially regulated in various tissues with a high level expression in flower tissues. In addition, the AtGSK1 expression was induced by NaCl and exogenously applied ABA but not by KCl. Taken together, these results suggest that AtGSK1 is involved in the osmotic stress response in Arabidopsis.

Characterization of two new channel protein genes in Arabidopsis

Aquaporins, small channel proteins, found in a variety of organisms are members of the major intrinsic protein (MIP) superfamily and have been shown to facilitate water transport when expressed in Xenopus oocytes. We isolated two Arabidopsis cDNAs, SIMIP and SITIP, that encode protein homologues of the MIP superfamily. SIMIP exhibits a high degree of sequence homology to PIP3 and MIP1, and thus may belong to the plasmamembrane intrinsic protein (PIP) subfamily, whereas salt-stress inducible tonoplast intrinsic protein (SITIP) is highly homologous to VM23 and gamma-TIP, and therefore may belong to the TIP subfamily. Expression studies revealed that the two genes showed a different expression pattern. The SIMIP gene was expressed in a tissue-specific manner, for example, its highest transcript level is found in flowers, relatively low levels in siliques, and very low level in leaves and roots. In contrast, SITIP was expressed in nearly equal amounts in all the tissues we examined. Also, the expression of SIMIP and SITIP showed a temporal regulation pattern. For example, the highest expression level was at 1 week after germination. In addition, the transcript levels of SIMIP and SMTIP were increased upon NaCl and ABA treatments. The biological function of the 2 genes were investigated using two NaCl stress-sensitive yeast mutant strains. The mutant yeast cells expressing these 2 genes were more resistant to high NaCl conditions. The results suggest that the proteins encoded by these genes may be involved in the osmoregulation in plants under high osmotic stress such as under a high salt condition.

Esophageal rupture during balloon dilation of strictures of benign or malignant causes: prevalence and clinical importance

PURPOSE

To review the prevalence and clinical importance of esophageal rupture during balloon dilation for treatment of esophageal stricture.

MATERIALS AND METHODS

Fluoroscopically guided esophageal balloon dilation was performed within 9 years in 96 consecutive patients with esophageal strictures. Esophageal rupture was classified into three types: type 1 was intramural; type 2, transmural; and type 3, transmural with mediastinal leakage.

RESULTS

Each patient underwent one to seven procedures, for a total of 191 procedures. Esophageal rupture occurred in 20 patients (21%). Type 1 esophageal rupture occurred in eight patients, type 2 in 11, and type 3 in one. All esophageal ruptures were detected immediately after the procedure. Sixteen patients were treated with fasting, parenteral alimentation, and antibiotics; two were treated surgically; and two were treated with stent placement. No treatment-related deaths occurred.

CONCLUSION

The overall prevalence of esophageal rupture was 21%. A substantial number of patients who developed type 1 rupture had associated clinical symptoms, such as pain and fever, but responded to conservative management and are thus included as having complications of esophageal balloon dilation.

Actinorhodin and undecylprodigiosin production in wild-type and relA mutant strains of Streptomyces coelicolor A3(2) grown in continuous culture

The effects of growth rate and nutrient feed rate on the production of actinorhodin (Act) and undecylprodigiosin (Red) were determined in Streptomyces coelicolor A3(2) and in a congenic relA null-mutant known to be deficient in ppGpp synthesis and antibiotic production under conditions of nitrogen limitation. In the relA+ strain, Act production was inversely related to specific growth rate in continuous cultures limited by glucose, ammonium, or phosphate, while Red biosynthesis was optimal at 0.05 h-1 regardless of the specific nutrient limitation. Production of Act and Red in the relA mutant was lower than that of the parental strain, particularly under conditions of glucose- and ammonium-limitation, indicating an important and general role for ppGpp in determining the onset of the antibiotic biosynthesis under conditions of nutrient limitation. At constant growth rate, but with varying nutrient feed rates, the specific rate of Act production was adversely influenced by increasing levels of glucose, ammonium, and phosphate, with phosphate having the greatest inhibitory effect. Under the same conditions, the specific rate of Red production was stimulated by increasing glucose levels, but markedly decreased by increased levels of phosphate.

Molecular cloning of an Arabidopsis cDNA encoding a dynamin-like protein that is localized to plastids

Dynamin-related proteins are high molecular weight GTPase proteins found in a variety of eukaryotic cells from yeast to human. They are involved in diverse biological processes that include endocytosis in animal cells and vacuolar protein sorting in yeast. We isolated a new gene, ADL2, that encodes a dynamin-like protein in Arabidopsis. The ADL2 cDNA is 2.68 kb in size and has an open reading frame for 809 amino acid residues with a calculated molecular mass of 90 kDa. Sequence analysis of ADL2 revealed a high degree of amino acid sequence similarity to other members of the dynamin superfamily. Among those members ADL2 was most closely related to Dnm1p of yeast and thus appears to be a member of the Vps1p subfamily. Expression studies showed that the ADL2 gene is widely expressed in various tissues with highest expression in flower tissues. In vivo targeting experiments showed that ADL2:smGFP fusion protein is localized to chloroplasts in soybean photoautroph cells. In addition experiments with deletion constructs revealed that the N-terminal 35 amino acid residues were sufficient to direct the smGFP into chloroplasts in tobacco protoplasts when expressed as a fusion protein.

Lacrimal system obstruction treated with lacrimal polyurethane stents: outcome of removal of occluded stents

PURPOSE

To describe the short- and long-term outcomes of the removal of occluded stents.

MATERIALS AND METHODS

With fluoroscopic guidance, 571 lacrimal polyurethane stents were placed in 502 patients with epiphora due to obstruction of the lacrimal system. Of the 571 stents, 142 were removed 2 weeks to 42 months (mean, 7 months) after placement because of recurrent epiphora, and the lacrimal system was irrigated with saline solution through the lacrimal point.

RESULTS

Stent removal was well tolerated. Mild epistaxis occurred in one patient and was controlled with a nasal pack. Recurrent epiphora was due to obstruction of the stent with mucoid material in 49 (35%) of 142 systems and granulation tissue in 93 (65%) systems. After stent removal, 73 (51%) of the 142 lacrimal systems showed improvement of epiphora, with a patent lacrimal system at 7-day follow-up dacryocystography. During the follow-up of 2 weeks to 49 months (mean, 22 months) after stent removal, patency was maintained in 24 (33%) of the 73 lacrimal systems.

CONCLUSION

Removal of an occluded lacrimal plastic stent was easy and safe. Recurrent epiphora after placement of lacrimal plastic stents can be treated with removal of the occluded stents an irrigation with saline solution through the lacrimal point, which resulted in a patent lacrimal system in 33% of cases in this study.

Molecular cloning of a novel Ca2+-binding protein that is induced by NaCl stress

Plant responses to high salt stress have been studied for several decades. However, the molecular mechanisms underlying these responses still elude us. In order to understand better the molecular mechanism related to NaCl stress in plants, we initiated the cloning of a large number of NaCl-induced genes in Arabidopsis. Here, we report the cloning of a cDNA encoding a novel Ca2+-binding protein, named AtCP1, which shares sequence similarities with calmodulins. AtCP1 exhibits, in particular, a high degree of amino acid sequence homology to the Ca2+-binding loops of the EF hands of calmodulin. However, unlike calmodulin, AtCP1 appears to have only three Ca2+-binding loops. We examined Ca2+ binding of the protein by a Ca2+-dependent electrophoretic mobility shift assay. A recombinant AtCP1 protein that was expressed in Escherichia coli did show a Ca2+-dependent electrophoretic mobility shift. To gain insight into the expression of the AtCP1 gene, northern blot analysis was carried out. The AtCP1 gene had a tissue-specific expression pattern: high levels of expression in flower and root tissues and nearly undetectable levels in leaves and siliques. Also, the expression of the AtCP1 gene was induced by NaCl treatment but not by ABA treatment. Finally, subcellular localization experiments using an AtCP1:smGFP fusion gene in soybean suspension culture cells and tobacco leaf protoplasts indicate that AtCP1 is most likely a cytosolic protein.

Effects of dopamine and estrogen on the regulation of Pit-1 alpha, Pit-1 beta, and PL-II gene expression in the rat placenta

Pituitary-specific transcription factor Pit-1 regulates growth hormone and prolactin gene expression in the pituitary. Recently, Pit-1 was shown to be locally synthesized in the rat placenta and is involved in the regulation of rat placental lactogen (PL) gene expression. Pit-1 has three different splicing variants. They are well known as being biologically active. In the present study, we found that Pit-1 beta is also synthesized in the rat placenta and we tried to examine the effects of dopamine and estrogen on the regulation of Pit-1 alpha, beta and PL-II genes expression using the reverse transcription-polymerase chain reaction (RT-PCR) and Northern blot hybridization. A dopamine receptor agonist, bromocriptine, significantly decreased placental Pit-1 alpha, beta, and PL-II mRNA levels. To examine the effect of estrogen on the gene expression of Pit-1 beta, pregnant female rats were ovariectomized (OVX) and injected daily with 17 beta-estradiol. OVX markedly lowered the amount of Pit-1 beta mRNA. Estrogen injection recovered the OVX-induced inhibition of Pit-1 beta mRNA level. Finally, we investigated the site-specific transcription of Pit-1 alpha and beta mRNA in the labyrinth zone and junctional zone of the placental in 15 and 20 days of gestation. The main site of Pit-1 alpha and beta synthesis was shifted from the junctional zone to the labyrinth zone from 15 to 20 days of gestation. Together, these data presume that Pit-1 beta may play a more important role in the placenta than in the pituitary and that Pit-1 may be involved in the regulation of the PL and prolactin-like peptide by estrogen and dopamine in the rat placenta.

Purification, characterization and molecular cloning of TGP1, a novel G-DNA binding protein from Tetrahymena thermophila

G-DNA, a polymorphic family of four-stranded DNA structures, has been proposed to play roles in a variety of biological processes including telomere function, meiotic recombination and gene regulation. Here we report the purification and cloning of TGP1, a G-DNA specific binding protein from Tetrahymena thermophila. TGP1 was purified by three-column chromatographies, including a G-DNA affinity column. Two major proteins (approximately 80 and approximately 40 kDa) were present in the most highly purified column fraction. Renaturation experiments showed that the approximately 80 kDa protein contains TGP1 activity. Biochemical characterization showed that TGP1 is a G-DNA specific binding protein with a preference for parallel G-DNAs. The TGP1/DNA complex has a dissociation constant (Kd) of approximately 2.2 x 10(-8) M and TGP1 can form supershift in gel mobility shift assays. The cDNA coding TGP1 was cloned and sequenced based upon an internal peptide sequence obtained from the approximately 80 kDa protein. Sequence analyses showed that TGP1 is a basic protein with a pI of 10.58, and contains two extensively hydrophilic and basic domains. Homology searches revealed that TGP1 is a novel protein sharing weak similarities with a number of proteins.

A dynamin-like protein in Arabidopsis thaliana is involved in biogenesis of thylakoid membranes

Dynamin, a GTP-binding protein found in rat brain, plays a role in endocytosis. Suborganellar fractionation studies of Arabidopsis leaf tissue revealed that a dynamin-like protein, ADL1, is localized in the thylakoid membranes of chloroplasts. This notion was supported further by in vivo targeting experiments using an ADL1-green fluorescent fusion protein and immunogold labeling with the anti-ADL1 antibody. Transgenic plants harboring various deletion mutant genes of ADL1 had a yellow leaf phenotype where the cells had very few chloroplasts. In addition, the remaining chloroplasts appeared morphologically not fully developed. The detailed structure of the chloroplasts revealed by electron microscopy showed a greatly reduced amount of thylakoid membranes. Also, the level of thylakoid membrane proteins such as the light-harvesting complex II and CP29 was greatly reduced in these transgenic plants. When we examined the expression of the ADL1 deletion mutant genes, these genes were highly expressed at the transcriptional level. However, the mutant ADL1s were not detectable at the protein level by Western blot analysis. Moreover, the endogenous ADL1 protein level was greatly reduced in these transgenic plants, probably due to a post-transcriptional silencing effect of the transgenes. We propose, therefore, that ADLl is involved in the biogenesis of thylakoid membranes.

Colocalization of dopamine D1 and D2 receptor mRNAs in rat placenta

Dopamine is present in the human placenta. The major function of dopamine is the inhibition of human placental lactogen (hPL) release from human trophoblastic cells. This effect is mediated by cAMP through dopamine D2 receptors. However, studies on the effects of cAMP in the control of hPL release have yielded conflicting results. The purpose of this study is to explore the distribution of dopamine receptors in the rat placenta. Dopamine D1 and D2 receptor mRNAs were colocalized in the rat placenta by in situ hybridization histochemistry using radiolabeled cRNA probes. Dopamine D1 and D2 receptor mRNAs were detected in large cells of the endometrium of the uterus on day 10 of gestation. On days 12-16 of gestation, hybridization signals were localized mainly in the spongiotrophoblast and giant cells of the junctional zone of the placenta. With the development of the placenta, signals were moving from the junctional zone to the labyrinth zone. Pit-1 mRNA was detected in the placental lactotrophs and was also colocalized in neighboring placental sections. Our results clearly showed that dopamine D1 and D2 receptor mRNAs were coexpressed in the placental lactotrophs that express Pit-1 mRNA.

Benign biliary strictures associated with recurrent pyogenic cholangitis: treatment with expandable metallic stents

OBJECTIVE

The purpose of this study was to determine the long-term effectiveness of expandable metallic stents in benign biliary strictures associated with recurrent pyogenic cholangitis and the differences in primary patency of the various types of stents deployed.

SUBJECTS AND METHODS

During a 20-month period, 26 metallic stents (19 Gianturco-Rosch Z stents and seven Strecker stents) were used to treat benign biliary strictures associated with recurrent pyogenic cholangitis in 23 patients (11 men and 12 women; mean age, 42 years; range, 30-78 years). Insertion routes were percutaneous transhepatic biliary drainage tracts for 16 stents, T-tube tracts for seven stents, and retrograde endoscopic routes for three stents. The deployed locations were common hepatic or common bile ducts for 11 stents, right or left hepatic ducts for 10 stents, and segmental ducts for five stents.

RESULTS

The initial technical success rate was 100%. Two stents in one patient migrated spontaneously. Primary stent patency for the remaining 24 stents was 34 months (range, 3-58 months). Primary stent patency of the Gianturco-Rosch Z and Strecker stents was 50 and 10 months, respectively (p < .05). Primary stent patency for the intrahepatic and extrahepatic ducts was 50 and 18 months, respectively (p = .05). Primary patency rates for all stents at 6, 12, 24, and 36 months were 92%, 75%, 67%, and 46%, respectively. The causes of stent obstruction were recurrent stone or sludge in eight stents and epithelial hyperplasia in five stents.

CONCLUSION

We believe that metallic stent placement is not an effective long-term treatment technique for benign biliary stricture associated with recurrent pyogenic cholangitis.

Prolonged ethanol intake increases D2 dopamine receptor expression in the rat brain

Dopamine via interaction with its receptor is known to be involved in the behavioral and endocrine actions in the mammalian brain. Behavioral effects produced by ethanol appear to be due to its actions on the dopaminergic system. In the present study using in situ hybridization histochemistry and RNase protection assay, the effect of prolonged ethanol intake on the expression of D2 dopamine receptor mRNA was examined in the rat brain. Specific D1 and D2 receptor mRNA signals were detected in the caudate putamen, nucleus accumbens, olfactory tubercle, hippocampus, dentate gyrus, and amygdaloid complex of the rat brain. Within the hypothalamus, the level of receptor mRNA was low in most nuclei with a somewhat higher level in the arcuate nucleus. Only the supurachiasmatic nucleus showed moderate to dense dopamine receptor mRNAs. Prefrontal cortex showed hybridization signals but their intensity was very low. A considerable amount of D2 mRNA was localized in the substantia nigra but D1 mRNA was not. Ethanol (10%) intake for 5 weeks increased both the density of hybridization signal and number of cells expressing D2 dopamine receptor mRNA in the caudate putamen, and nucleus accumbens, but not in the olfactory tubercle. RNase protection assay revealed about a 1.5-fold increase in the D2 dopamine receptor mRNA level in the corpus striatum. These results provide a basis for the involvement of dopamine D2 receptor expression in alcoholism.

Cloning, sequencing and analysis of cDNA encoding bovine intercellular adhesion molecule-1 (ICAM-1)

Intercellular adhesion molecule-1 (ICAM-1) is an inducible glycoprotein that interacts with the leukocyte beta 2-integrins, LFA-1 and Mac-1. We have isolated and analyzed a cDNA clone coding for the putative bovine ICAM-1 gene and compared it with known comparative sequences from other species as well as bovine ICAM-3. The 3398-bp bovine ICAM-1 cDNA sequence codes for 535 amino acids and shows 57% homology with human ICAM-1 and 47% homology with bovine ICAM-3 at the amino acid levels. The predicted number and positions of cysteine residues in bovine ICAM-1 are all conserved among species including bovine ICAM-3. It has two arginine-glycine-aspartate (RGD) sites in the extracellular region and a serine residue in the cytoplasmic tail. Northern blot results show that the bovine ICAM-1 gene is expressed in stimulated leukocytes whereas bovine ICAM-3 is expressed predominantly in resting neutrophils.

A dynamin-like protein, ADL1, is present in membranes as a high-molecular-mass complex in Arabidopsis thaliana

Dynamin, a GTP-binding protein, is involved in endocytosis in animal cells. We found that a dynamin-like protein, ADL1, is present in multiple forms in Arabidopsis leaf tissue. Subcellular fractionation experiments, together with gel-filtration and nondenaturing-gel electrophoresis revealed that most of ADL1 is present as a high-molecular-mass complex of 400 to 600 kD in the membrane or pellet fraction, whereas ADL1 is present in the soluble fraction as a monomer. The subcellular distribution of ADL1 is affected by various agents such as Ca2+, cyclosporin A, GTP, and ATP. Ca2+ increases the amount of ADL1 present in the membrane fraction, whereas cyclosporin A inhibits the membrane association. Furthermore, Ca2+ and GTP change the migration pattern of ADL1 in nondenaturing polyacrylamide gels, indicating that these chemicals influence either the complex formation and/or the conformation of the ADL1 complex. Our results demonstrate that ADL1 has characteristics that are similar to Dynamin I, which is found in animal cells. Therefore, it is possible that ADL1 is also involved in biological processes that require vesicle formation.

Isolation of molecular markers for salt stress responses in Arabidopsis thaliana

Characterization of many osmotic stress-induced genes has greatly contributed to the understanding of the physiological responses of plant cells to osmotic stress at the molecular level. In this study we constructed a subtraction library and generated 15 salt stress-inducible ESTs from this library to use as molecular markers that reflect the cellular responses to salt stress responses in Arabidopsis. The sequence analysis showed that 5 salt stress-inducible ESTs were identical to previously identified genes in Arabidopsis, 6 cDNAs were homologous to known genes found in plants as well as yeast, and 4 cDNAs were new genes. To confirm that expression of these clones are induced by salt stress, we carried out Northern blot analysis. When we examined for 15 cDNA clones, they were indeed induced by NaCl treatment. The induction level was variable among these genes ranging from approximately 2-fold to more than 50-fold. Also, Northern blot analysis revealed that these genes can be divided into three different induction patterns: early induction, late induction, and continuous induction.