Mini-detachable snare ligation for the treatment of esophageal varices

BACKGROUND

We manufactured and studied the usefulness of a newly designed mini-detachable snare in the treatment of esophageal varices. The use of a multiple rubber band ligator, although generally effective and well tolerated, has certain limitations, including high cost, reduced visual field, and inadvertent band release.

METHODS

We performed a prospective randomized controlled trial of the use of mini-detachable snare ligation vs. multiple band ligation in patients with recent or active esophageal variceal bleeding. The outcomes assessed were immediate hemostasis and rates of recurrent bleeding, eradication, and recurrence.

RESULTS

From March 1997 to October 1998, 103 patients were entered into this trial; 46 underwent mini-detachable snare ligations and 57 multiple band ligations. Among patients with active bleeding, hemostasis was achieved in 6 of 7 (86%) in the mini-detachable snare ligation group and 11 of 13 (85%) in multiple band ligation group. Recurrent bleeding after initial treatment occurred in 2 of 46 (5.5%) in the mini-detachable snare ligation group and 3 of 57 (5.3%) in the multiple band ligation group. Esophageal varices were eradicated or reduced to grade I in 4.8 +/- 2.1 and 4.5 +/- 1.9 sessions in the mini-detachable snare ligation group and multiple band ligation group, respectively. The recurrence rate was 5 of 46 (11%) and 6 of 57 (11%) in the mini-detachable snare ligation group and multiple band ligation group during a follow-up period of 6 and 16 months, respectively. No serious complication occurred in either group.

CONCLUSION

The mini-detachable snare is a new device that provides safe and effective treatment for esophageal varices that is comparable to multiple band ligation.

Birth after the injection of sperm and the cytoplasm of tripronucleate zygotes into metaphase II oocytes in patients with repeated implantation failure after assisted fertilization procedures

OBJECTIVE

To assess the technique of injecting a single sperm and cytoplasm obtained from tripronucleate zygotes into metaphase II oocytes for the treatment of patients with repeated implantation failure after intracytoplasmic sperm injection or IVF.

DESIGN

Clinical study.

SETTING

Private infertility clinic.

PATIENT(S)

Patients with repeated implantation failure after intracytoplasmic sperm injection or IVF.

INTERVENTION(S)

The metaphase II oocytes of recipients were injected with their husbands' spermatozoa and cytoplasm aspirated from the tripronucleate zygotes of donors.

MAIN OUTCOME MEASURE(S)

Fertilization after cytoplasm and sperm injection, embryo development, and successful pregnancy.

RESULT(S)

In total, 62 metaphase II oocytes from nine recipients were injected. Of the 62 injected oocytes, 3 (5%) degenerated and 43 (69%) had two pronuclei 18 hours after injection. Thirty-nine oocytes with two pronuclei cleaved to the two-cell to six-cell stage after another 24 hours of culture. All cleaved embryos were transferred into the uteruses of recipients. Four clinical pregnancies occurred in four recipients. No abnormal chromosomes were observed after amniocentesis and karyotyping in all pregnancies. Five healthy infants were born.

CONCLUSION(S)

Injection of the cytoplasm of tripronucleate zygotes may enhance the clinical pregnancy rate in patients with repeated implantation failure after intracytoplasmic sperm injection or IVF.

Cloning and analysis of the aroB gene encoding dehydroquinate synthase from Corynebacterium glutamicum

The aroB gene encoding dehydroquinate synthase of Corynebacterium glutamicum has been cloned by complementation of an aro auxotrophic mutant of Escherichia coli with the genomic DNA library. The recombinant plasmid contained a 1.4-kb fragment that complemented the Escherichia coli dehydroquinate-synthase-deficient mutant. The nucleotide sequences of the subcloned DNA has been determined. The sequences contain an open reading frame of 360 codons, from which a protein with a molecular mass of about 38 kDa could be predicted. This is consistent with the size of the AroB protein expressed in E. coli. Alignment of different prokaryotic and eukaryotic aroB gene products reveals an overall identity ranging from 29 to 57% and the presence of several highly conserved regions.

Evaluation and management of lateral ankle injuries

The diagnosis and management of lateral ankle injuries require the physician to obtain an accurate history, complete a thorough physical examination, and institute appropriate treatment protocol. Labeling all acute lateral ankle injuries as ankle sprains can lead to long-term mechanical and functional instability and chronic pain around the ankle. Appropriate and aggressive functional rehabilitation of the acute ankle limits the postinjury convalescence and need for surgical reconstruction. If surgical repair of the chronic or acute ankle is warranted, the Brostrom-Gould procedure serves as a highly successful anatomic repair. Lateral ankle tenodesing procedures also are effective; however, in most cases, the loss of rearfoot motion limits this procedure to a secondary reconstructive procedure.

c-Myc expression is related with cell proliferation and associated with poor clinical outcome in human gastric cancer

We underwent protein assay for Myc expression in 76 human gastric cancer tissues using immunohistochemistry. Expression of Myc protein was analyzed according to proliferative indices measured by flow cytometry. Levels of Myc protein expression was evaluated by correlating with biologic and clinical parameters. In 36 (47.4%) of 76 primary gastric cancers, overexpression of Myc was observed. We could observe expression of Myc protein in a significant portion of early gastric cancer (42.9%). Expression of Myc protein was demonstrated to be more frequent in poorly differentiated cancer cells (p=0.043). However, expression of Myc protein had little influence over progress or extent of the disease. Expression of Myc protein was significantly correlated with increased proliferative activity (p=0.032) and patients with high levels of Myc expression had poor disease-free survival. In a certain proportion of human gastric cancer, Myc protein may function as a regulator of cancer cell growth and expression of Myc may represent an aggressive phenotype of gastric cancer.

Comparison of Gadomer-17 and Gd-DTPA in image quality of contrast-enhanced MR angiographies using flow phantom model

The purpose of this study was to compare the image quality of 3D-TOF MR angiography (MRA) using Gadomer-17 with that using Gd-DTPA in a flow phantom model, and to present preliminary data about the proper dose concentration of Gadomer-17. In the visual analysis of vessel conspicuity, we compared the quality of pre- and post-contrast MIP images. For quantitative analysis, the signal intensities were measured in the axial base 3D-TOF images, and then the relative contrast enhancement was calculated. The results of our studies were that: 1. Maximal signal intensities were obtained at 1 mmol/L of Gadomer-17 and 4 mmol/L of Gd-DTPA. 2. Flow-related signal loss was decreased by Gd-DTPA proportional to the concentration, but Gadomer-17 did not show such a dose accumulative effect. In conclusion, after comparing the results of Gd-DTPA, it was clear that improved MRA images and higher signal intensities of vessels were obtained when lower concentrations of Gadomer-17 were used.

Regulation of selection of liver nodules initiated with N-nitrosodiethylamine and promoted with nodularin injections in fischer 344 male rats by reciprocal expression of transforming growth factor-beta1 and its receptors

To investigate how glutathione-S-transferase placental form (GST-P)+ hyperplastic nodules (HNs) are selected and to determine the driving force for progression or regression of HNs, changes in transforming growth factor-beta1 (TGF-beta) and its receptors were examined during hepatocarcinogenesis initiated by N-nitrosodiethylamine (DEN) and promoted by nodularin. The induction of TGF-beta1 expression in the GST-P+ HNs was dependent on nodularin injections for 10 wk, which started the third week after DEN initiation. The kinetics of TGF-beta1 induction during carcinogenesis were quite different from that of simple regeneration after partial hepatectomy (PH): hepatocytes initiated with DEN alone induced TGF-beta1 expression for 24 d, and subsequent stimulation by PH on the fourteenth day after DEN initiation super-induced TGF-beta1 mRNA (50 times that of the control level), as opposed to a transient expression for less than 5 d by PH alone. GST-P+ HNs did not express TGF-beta receptors I (RI) and II (RII) during the early stage of carcinogenesis, whereas the surrounding hepatocytes strongly expressed both of these receptors. On cessation of nodularin injection, however, the expression of RI and RII in the HNs changed significantly: RII+ nodules appeared, and the number and area of RII+/- nodules were significantly increased at 10 wk after the cessation. These findings indicate that induction of TGF-beta expression in GST-P+ HNs might be a strong selection pressure that allows outgrowth of RII- nodules during liver carcinogenesis.

The use of toluidine blue gargles to aid the detection of impacted pharyngeal fish bones

Fishbone impaction is a common clinical problem. In most cases careful examination pinpoints the impacted bone which can then be removed. If no bone is detected a distinction must be drawn between mucosal abrasion mimicking fishbone impaction and a fine or deeply impaled fishbone eluding detection. We present a new method that may be helpful in the detection of pharyngeal fishbones.

Reciprocal inhibition between the forearm muscles in patients with paroxysmal kinesigenic dyskinesia

We measured the changes of forearm flexor H reflexes produced by conditioning radial nerve stimulation at delays of -2, 0, 2, 4, 7.5, 10, 25 and 75 ms in 10 patients with PKD and six with generalized seizure disorder. We compared the results with 12 normal volunteers. In the patients with PKD, we compared the amounts of reciprocal inhibition between the severely and the asymptomatic or mildly affected sides of arms. Follow-up studies were done in eight PKD patients after they responded to the anticonvulsant treatment. At each delay, patients with seizure disorders showed comparable amounts of changes with controls. Patients with PKD showed paradoxical facilitation at a delay of 0 ms, enhanced facilitation between 2 to 7.5 ms delays and attenuated inhibition at a delay of 75 ms. There were no significant differences in the amount of reciprocal inhibition according to the severity of clinical symptoms. Follow-up studies showed no significant changes of reciprocal inhibition compared to the baseline data. In PKD, paradoxical facilitation and enhanced first relative facilitation period may be caused by defective spinal interneurons. In addition to the defective reciprocal inhibition, abnormalities of supraspinal inputs seem to be involved in the genesis of PKD.

The modified Lapidus arthrodesis: a retrospective analysis

The authors present a review of 47 modified Lapidus arthrodesis procedures performed between 1985 and 1995. There were 29 females and 10 males. Eight patients underwent bilateral procedures. The average follow-up was 6.3 years (range, 1.5-10.6 years). The patients were evaluated preoperatively and postoperatively using standard weightbearing radiographs, clinical examination, and chart review. The average preoperative intermetatarsal angle was 13.8 degrees degrees, and the average postoperative intermetatarsal angle measured 2.1 degrees degrees, with a mean improvement of 10.8 degrees. The average effective shortening of the first metatarsal was 4.7 mm in those patients without bone graft. In patients whom bone graft was utilized, an average effective increase in first metatarsal length of 2.6 mm was identified. Complications included delayed union (n = 2), nonunion (n = 3), postoperative development of hyperkeratosis beneath the second metatarsal head (n = 4), elevation of the first ray (n = 3), and hallux varus (n = 2). There were no recurrences of hallux abducto valgus at follow-up. The average return to preoperative activity level was 13 weeks. Forty-two of the 47 procedures healed uneventfully. Of the remaining five feet, two required the use of a bone growth stimulator, and three required revisional surgery with autogenous bone graft to promote arthrodesis and restore alignment. In conclusion, the modified Lapidus arthrodesis is both a predictable and durable procedure for the correction of hallux abducto valgus.

Molecular clock calibrations and metazoan divergence dates

It has recently been argued that living metazoans diverged over 800 million years ago, based on evidence from 22 nuclear genes for such a deep divergence between vertebrates and arthropods (Gu 1998). Two "internal" calibration points were used. However, only one fossil divergence date (the mammal-bird split) was directly used to calibrate the molecular clock. The second calibration point (the primate-rodent split) was based on molecular estimates that were ultimately also calibrated by the same mammal-bird split. However, the first tetrapods that can be assigned with confidence to either the mammal (synapsid) lineage or the bird (diapsid) lineage are approximately 288 million years old, while the first mammals that can be assigned with confidence to either the primate or the rodent lineages are 65 million years old, or 85 million years old if ferungulates are part of the primate lineage and zhelestids are accepted as ferungulate relatives. Recalibration of the protein data using these fossil dates indicates that metazoans diverged between 791 and 528 million years ago, a result broadly consistent with the palaeontological documentation of the "Cambrian explosion." The third, "external" calibration point (the metazoan-fungal divergence) was similarly problematic, since it was based on a controversial molecular study (which in turn used fossil dates including the mammal-bird split); direct use of fossils for this calibration point gives the absurd dating of 455 million years for metazoan divergences. Similar calibration problems affect another recent study (Wang et al. 1999), which proposes divergences for metazoans of 1000 million years or more: recalibrations of their clock again yields much more recent dates, some consistent with a "Cambrian explosion" scenario. Molecular clock studies have persuasively argued for the imperfection of the fossil record but have rarely acknowledged that their inferences are also directly based on this same record.

Effects of ChunDoSunBup Qi-training on growth hormone, insulin-like growth factor-I, and testosterone in young and elderly subjects

We observed the response of plasma growth hormone (GH), insulin-like growth factor-I (IGF-I) and testosterone (T) to an acute period of ChunDoSunBup (CDSB) Qi-training. Although the basal level of GH was not different between the two groups, after the portion of the training in which the subjects were physically active (the mid-training point), plasma GH levels increased by 7.26 fold (p < 0.05) in the elderly trainees and by 1.66 fold (p < 0.05) in the young. In response to CDSB Qi-training, IGF-I levels in the young increased significantly at mid-training point, but there were no increase in the elderly. Significant correlations existed between GH and IGF-I levels in the young subjects, but not in the elderly. The T level at the mid-training point increased significantly in elderly subjects but not in the young. These results suggest that CDSB Qi-training is a potential method for modulating of the secretion of growth factor in the young and the elderly, but that the elderly IGF-I response does not equal that of the young. In addition, our study suggests CDSB Qi-training may be one mode of therapy applicable to growth factor related disorders such as GH deficiency in children and osteoporosis in the elderly, especially women.

Fas is expressed in murine pancreatic islet cells and an insulinoma cell line but does not mediate their apoptosis in vitro

CD4+ lymphocytes are the most important effector cells in autoimmune diabetes of NOD mice, although some role of CD8+ T cells has been demonstrated. However, it is unknown how CD4+ lymphocytes are able to destroy pancreatic beta-cells that do not express MHC (major histocompatibility complex) class II molecules. Apoptotic cell death mediated by an interaction of Fas with Fas ligand (FasL) could be a mechanism by which MHC class II-negative pancreatic beta-cells are destroyed by CD4+ T lymphocytes. We have examined the expression of Fas molecules in pancreatic islet cells, as well as in a NOD-derived mouse insulinoma cell line (MIN6N8). In addition, the role of Fas-mediated apoptosis in pancreatic islet cell death was explored in vitro. Although Fas expression was not detected by flow cytometric analysis, Fas transcripts were demonstrated in MIN6N8 cells and pancreatic islet cells by the sequencing analysis of the cloned reverse transcription polymerase chain reaction products using Fas-specific primers. IFN (interferon)-gamma, tumor necrosis factor-alpha, interleukin-1 and their combinations failed to enhance Fas expression. Unsorted activated splenocytes from diabetic NOD mice had cytotoxic T lymphocyte activity of a small degree against IFN-gamma-treated MIN6N8 cells with FasL upregulation. However, agonistic anti-Fas antibody with or without cycloheximide did not exert cytotoxicity against MIN6N8 cells or pancreatic islets. FasL transfectant cells also did not kill MIN6N8 cells. Our data indicate that pancreatic beta-islet cells express a small amount of Fas molecules but Fas molecules do not mediate apoptosis of islet cells at least in vitro.

Differential expression of O6-methylguanine-DNA methyltransferase during diethylnitrosamine-induced carcinogenesis and liver regeneration in Sprague-Dawley male rats

Differential expression of DNA-O6MeG: protein-L-cysteine S-methyltransferase (MGMT) activity and posttranslational modification of the protein during liver regeneration and carcinogenesis were compared in Sprague-Dawley male rats after partial hepatectomy and/or single i.p injection of diethylnitrosamine (DEN, 200 mg/kg). Regenerating hepatocytes after partial hepatectomy induced MGMT transiently within 3 days; however, the induction of MGMT was persistent for 2 weeks after DEN injection, and the combined treatment of DEN and partial hepatectomy maintained the elevated MGMT level for up to 4 weeks. The increased activity was transcriptionally regulated, when analyzed by Northern blot hybridization. The major active form of MGMT protein in the partially hepatectomized or DEN-treated rats was a 26-kDa or 24-kDa species respectively, which was confirmed by Western blot analysis and gel slice assay. The biological significance of the differential induction of MGMT during partial hepatectomy or DEN-induced carcinogenesis is not obvious; however, further studies on possible posttranslational modifications of MGMT protein might shed some light on the functional aspect of MGMT induction.

Vitamin A deficiency phrynoderma: due to malabsorption and inadequate diet

We describe a patient with vitamin A deficiency phrynoderma caused by a combination of inadequate dietary intake of vitamin A and beta-carotene and malabsorption secondary to primary visceral myopathy and total colectomy.

Identification of a new regulator in Streptococcus pneumoniae linking quorum sensing to competence for genetic transformation

Competence for genetic transformation in Streptococcus pneumoniae is regulated by a quorum-sensing system encoded by two genetic loci, comCDE and comAB. Additional competence-specific operons, cilA, cilB, cilC, cilD, cilE, cinA-recA, coiA, and cfl, involved in the DNA uptake process and recombination, share an unusual consensus sequence at -10 and -25 in the promoter, which is absent from the promoters of comAB and comCDE. This pattern suggests that a factor regulating transcription of these transformation machinery genes but not involved with comCDE and comAB expression might be an alternative sigma factor. A search for such a global transcriptional regulator was begun by purifying pneumococcal RNA polymerase holoenzyme. In preparations from competent pneumococcal cultures a protein which seemed to be responsible for cilA transcription in vitro was identified. The corresponding gene was identified and found to be present in two copies, designated comX1 and comX2, located adjacent to two of the repeated rRNA operons. Expression of transformation machinery operons, such as cilA, cilD, cilE, and cfl, but not that of the quorum-sensing operons comAB and comCDE, was shown to depend on comX, while comX expression depended on ComE but not on ComX itself. We conclude that the factor is a competence-specific global transcription modulator which links quorum-sensing information transduced to ComE to competence and propose that it acts as an alternate sigma factor. We also report that comAB and comCDE are not sufficient for shutoff of competence-stimulating peptide-induced gene expression nor for the subsequent refractory period, suggesting that these phenomena depend on one or more ComX-dependent genes.

Uncoupling of the hnRNP Npl3p from mRNAs during the stress-induced block in mRNA export

Npl3p, the major mRNA-binding protein of the yeast Saccharomyces cerevisiae shuttles between the nucleus and the cytoplasm. A single amino acid change in the carboxyl terminus of Npl3p (E409 --> K) renders the mutant protein largely cytoplasmic because of a delay in its import into the nucleus. This import defect can be reversed by increasing the intracellular concentration of Mtr10p, the nuclear import receptor for Npl3p. Conversely, using this mutant, we show that Npl3p and mRNA export out of the nucleus is significantly slowed in cells bearing mutations in XPO1/CRM1, which encodes the export receptor for NES-containing proteins and in RAT7, which encodes an essential nucleoporin. Interestingly, following induction of stress by heat shock, high salt, or ethanol, conditions under which most mRNA export is blocked, Npl3p is still exported from the nucleus. The stress-induced export of Npl3p is independent of both the activity of Xpo1p and the continued selective export of heat-shock mRNAs that occurs following stress. UV-cross-linking experiments show that Npl3p is bound to mRNA under normal conditions, but is no longer RNA associated in stressed cells. Taken together, we suggest that the uncoupling of Npl3p and possibly other mRNA-binding proteins from mRNAs in the nucleus provides a general switch that regulates mRNA export. By this model, under normal conditions Npl3p is a major component of an export-competent RNP complex. However, under conditions of stress, Npl3p no longer associates with the export complex, rendering it export incompetent and thus nuclear.

Diversity of core promoter mutations in immune clearance phase of chronic HBV infection

BACKGROUND/AIMS

Transcription of HBV (hepatitis B virus) pre-core and pre-genomic mRNAs is controlled by core promoter. Therefore, mutations in the core promoter region might change the activity of liver diseases through an altered transcriptional level of the mRNA. The present study was carried out to determine the diversity of HBV core promoter sequences in chronic HBV carriers.

METHODS

DNA sequences in the core promoter region were determined after cloning the PCR product. Two groups of chronic HBV carriers with HBeAg, including five cases of asymptomatic carriers (ASCs, 21 clones) and eight with chronic hepatitis (CH, 50 clones) were studied.

RESULTS

Mutations in the core promoter were found in three out of the ASCs (11 clones), and in all eight cases in the CH group (48 clones). While mutations at nucleotide 1762 (A-->T) and 1764(G-->A) were not found in ASC, mutations at the same positions were found in all the cases of CH group (40 clones) (P=0.003). Diverse patterns of mutations in the core promoter were observed in each patient in the CH group.

CONCLUSIONS

Further studies are needed to determine whether the diversity of HBV core promoter mutations has clinical significance such as the seroconversion of HBeAg to anti-HBe.

Enlistment of combinatorial techniques in drug development

Combinatorial chemistry, in its ability to generate vast arrays of non-peptide and non-oligonucleotide libraries, has had a major impact on the drug discovery effort. The design and generation of a combinatorial library, coupled with the ever important and effective feedback from high-throughput screening and data management, are critical to any drug discovery process. This review will focus on some aspects of computational chemistry, solid-phase organic chemistry and downstream analysis. The emphasis will be on computational aspects of library design and the use of cyclic scaffolds in the context of a focused library for optimization in drug discovery.

Expression of p27Kip1 and cyclin D1 proteins is inversely correlated and is associated with poor clinical outcome in human gastric cancer

BACKGROUND AND OBJECTIVES

p27Kip1 is an inhibitor of cyclin-dependent kinases and is speculated to be a potential prognostic indicator in numerous human cancers. We investigated expression of p27Kip1 along with cyclin D1 in gastric cancer to estimate the clinical utility of p27Kip1.

METHODS

Immunohistochemical assay for p27Kip1 and cyclin D1 proteins was performed in 64 patients with primary gastric cancer. Correlation between p27Kip1 expression and clinical-biological parameters including patient survival was analyzed.

RESULTS

p27Kip1 expression was suppressed in 40 (62.5%) of 64 gastric cancer patients and cyclin D1 was overexpressed in 22 (34.4%) out of 64. Expression of p27Kip1 was significantly reduced in poorly differentiated cancers (82.1%, 23/28; P = 0.015) and was also reduced in the tumors with high S-phase fraction (86.7%, 26/30) compared with tumors showing low S-phase fraction (41.2%, 14/34; P = 0.0002). Expression of p27Kip1 and cyclin D1 was inversely correlated (P = 0.021). In univariate analysis, extent of the disease (P < 0.001), expression of cyclin D1 (P = 0.0001), and reduced expression of p27Kip1 (P = 0. 0006), were statistically significant to predict patient's outcome, but depth of invasion (P = 0.008) and pathologic stage (P = 0.009) emerged as significant prognostic indicators in multivariate analysis.

CONCLUSION

Expression of p27Kip1 is closely linked with cell proliferation and differentiation of human gastric cancer. p27Kip1 seems to have potential as a prognostic marker in the management of gastric cancer patients.

Laser-induced drusen reduction improves visual function at 1 year. Choroidal Neovascularization Prevention Trial Research Group

OBJECTIVE

To describe the relationship of laser-induced drusen reduction to change in visual function at 1 year among patients enrolled in the Choroidal Neovascularization Prevention Trial (CNVPT).

DESIGN

Comparison of groups with and without drusen reduction; follow-up of a randomized controlled trial.

PARTICIPANTS

Evaluations of drusen and visual acuity at baseline and at 1 year were performed for 351 eyes of the 432 eyes enrolled in the CNVPT Bilateral Drusen Study and Fellow Eye Study (81%). One hundred eighty-four eyes were assigned to observation, and 167 eyes were assigned to laser treatment. Eyes with conditions that precluded an analysis of drusen reduction, such as those that developed choroidal neovascularization (CNV) within the first year, are excluded from this analysis.

METHODS

Change in macular drusen between initial visit and after 1 year was assessed by side-by-side grading by evaluators masked to information on visual function. Visual acuity, contrast threshold, and critical print size were measured by certified visual function examiners.

MAIN OUTCOME MEASURES

Change in visual acuity is the primary outcome. Change in contrast threshold and change in critical print size are secondary outcome measures.

RESULTS

Laser-treated eyes with 50% or more drusen reduction at 1 year had more 1- and 2-line increases in visual acuity and less losses in visual acuity compared with laser-treated eyes with less drusen reduction or with observed eyes (P = 0.001). Similar improvements were noted for contrast threshold but not critical print size at 1 year.

CONCLUSIONS

Laser-induced drusen reduction is associated with improved visual acuity and contrast sensitivity in eyes at 1 year. Longer term effects of laser-induced drusen reduction on visual function require additional observation. The overall potential value of laser treatment in eyes with high-risk drusen requires consideration of not only short-term effects on vision but also the effects of CNV and atrophy on vision.

Studies on constituents with cytotoxic activity from the stem bark of Syringa velutina

Cytotoxic compounds, oleuropein (1) and a phenylethanoid glycoside (2) were isolated from the stem bark of Syringa velutina KOM. along with coniferylaldehyde 4-O-glucoside, syringin, ligstroside, (+)-syringaresinol 4-O-glucoside, (+)-medioresinol 4"-O-glucoside and (-)-olivil 4"-O-glucoside. Phenylethanoid glycoside (2) was identified to be 3,4-dihydroxyphenylethyl alcohol 8-O-beta-D-glucopyranoside. This compound showed the most potent cytotoxic effect on several tumor cell lines (P-388, L-1210, SNU-5 and HL-60) among eight compounds isolated in the present study. We suggest that the 3,4-dihydroxyphenylethoxy moiety of this compound contributes to cytotoxicity.

Cloning of the argF gene encoding the ornithine carbamoyltransferase from Corynebacterium glutamicum

The argF gene encoding ornithine carbamoyl-transferase (OTCase; EC2.1.3.3) has been cloned from Corynebacterium glutamicum by transforming the Escherichia coli arginine auxotroph with the genomic DNA library. The cloned DNA also complements the E. coli argG mutant, suggesting a clustered organization of the genes in the genome. We have determined the DNA sequence of the minimal fragment complementing the E. coli argF mutant. The coding region of the cloned gene is 957 nucleotides long with a deduced molecular mass of about 35 kDa polypeptide. The enzyme activity and size of the expressed protein in the E. coli auxotroph carrying the argF gene revealed that the cloned gene indeed codes for OTCase. Analysis of the amino acid sequence of the predicted protein revealed a strong similarity to the corresponding protein of other bacteria.

RNA polymerase-specific nucleosome disruption by transcription in vivo

The nucleosomal chromatin structure within genes is disrupted upon transcription by RNA polymerase II. To determine whether this disruption is caused by transcription per se as opposed to the RNA polymerase source, we engineered the yeast chromosomal HSP82 gene to be exclusively transcribed by bacteriophage T7 RNA polymerase in vivo. Interestingly, we found that a fraction of the T7-generated transcripts were 3' end processed and polyadenylated at or near the 3' ends of the hsp82 and the immediately downstream CIN2 genes. Surprisingly, the nucleosomal structure of the T7-transcribed hsp82 gene remained intact, in marked contrast to the disrupted structure generated by much weaker, basal level transcription of the wild type gene by RNA polymerase II under non-heat shock conditions. Therefore, disruption of chromatin structure by transcription is dependent on the RNA polymerase source. We propose that the observed RNA polymerase dependence for transcription-induced nucleosome disruption may be related either to the differential recruitment of chromatin remodeling complexes, the rates of histone octamer translocation and nucleosome reformation during polymerase traversal, and/or the degree of transient torsional stress generated by the elongating polymerase.