MST, a physiological caspase substrate, highly sensitizes apoptosis both upstream and downstream of caspase activation

The human serine/threonine kinase, mammalian STE20-like kinase (MST), is considerably homologous to the budding yeast kinases, SPS1 and STE20, throughout their kinase domains. The cellular function and physiological activation mechanism of MST is unknown except for the proteolytic cleavage-induced activation in apoptosis. In this study, we show that MST1 and MST2 are direct substrates of caspase-3 both in vivo and in vitro. cDNA cloning of MST homologues in mouse and nematode shows that caspase-cleaved sequences are evolutionarily conserved. Human MST1 has two caspase-cleavable sites, which generate biochemically distinct catalytic fragments. Staurosporine activates MST either caspase-dependently or independently, whereas Fas ligation activates it only caspase-dependently. Immunohistochemical analysis reveals that MST is localized in the cytoplasm. During Fas-mediated apoptosis, cleaved MST translocates into the nucleus before nuclear fragmentation is initiated, suggesting it functions in the nucleus. Transiently expressed MST1 induces striking morphological changes characteristic of apoptosis in both nucleus and cytoplasm, which is independent of caspase activation. Furthermore, when stably expressed in HeLa cells, MST highly sensitizes the cells to death receptor-mediated apoptosis by accelerating caspase-3 activation. These findings suggest that MST1 and MST2 play a role in apoptosis both upstream and downstream of caspase activation.

Endonasal endoscopic removal of growth-hormone-secreting pituitary adenomas

Trans-sphenoidal removal of pituitary tumours using the endonasal endoscopic technique, a novel application, is herein reported in five consecutive patients with growth-hormone-secreting pituitary adenomas seen at a teaching hospital in Hong Kong. All five patients demonstrated complete tumour removal on postoperative imaging and hormonal assessment following the procedure. Surgical morbidity and symptoms were minimal; postoperative obstructive nasal packing was not required with this technique, which greatly improved patient comfort. Preliminary experience suggests that the endonasal endoscopic approach is a safe and effective alternative to the conventional trans-septal microscopic method for the treatment of pituitary tumour. A randomised controlled trial comparing these two approaches is currently underway at this institution.

Differential inheritance modes of DNA methylation between euchromatic and heterochromatic DNA sequences in ageing fetal bovine fibroblasts

To elucidate overall changes in DNA methylation occurring by inappropriate epigenetic control during ageing, we compared fetal bovine fibroblasts and their aged neomycin-resistant versions using bisulfite-PCR technology. Reduction in DNA methylation was observed in euchromatic repeats (18S-rRNA/art2) and promoter regions of single-copy genes (the cytokeratin/beta-lactoglobulin/interleukin-13 genes). Contrastingly, a stable maintenance of DNA methylation was revealed in various heterochromatic sequences (satellite I/II/alphoid and Bov-B). The differential inheritance mode of DNA methylation was confirmed through the analysis of individual neomycin-resistant clones. These global, multi-locus analyses provide evidence on the tendency of differential epigenetic modification between genomic DNA regions during ageing.

Parvalbumin Expression Is Downregulated in Rat Fast-Twitch Skeletal Muscles during Aging

In this study, the protein expression profile of extensor digitorum longous (EDL) and Soleus (SOL) muscles, representing fast- and slow-twitch skeletal muscles, respectively, was established using high resolution two-dimensional electrophoresis (2-DE). One protein spot was found uniquely expressed in EDL muscle. N-terminal sequence analysis identified the protein as parvalbumin. Parvalbumin is a high affinity calcium binding protein that regulates muscle contraction and relaxation. Our experiments revealed that parvalbumin expression in EDL muscle was down-regulated during aging. In addition, high-intensity exercise could reverse this age-related change. Soleus muscles do not normally express parvalbumin, but high-intensity exercise could ectopically induce its expression in both young and old SOL muscles. We have also confirmed our 2-DE findings by immunohistochemistry on muscle sections. Our results suggest that high-intensity training could be used to improve muscle functions during aging because parvalbumin play an important role in regulating skeletal muscle contraction and relaxation.

A case of malignant proliferating trichilemmoma of the scalp with multiple metastases

We report a case of malignant proliferating trichilemmal tumor showing multiple distant metastases. The patient demonstrated a round mass in the right occipital area for 12 months and the lesion grew rapidly to assume 8 x 6.5 x 4 cm in diameter, with areas of superficial erosion and crusting within the recent 3 months. The entire lesion was removed with a wide surgical excision. It recurred on the neck area 4 months after excision and the lesion was removed with surgical resection again. There was evidence of multiple metastases on CNS and mediastinal lymph nodes after 6 months. The patient was treated with cisplatin and etoposide combination chemotherapy and a partial response was achieved.

Overexpression of membrane-type matrix metalloproteinase-1 gene induces mammary gland abnormalities and adenocarcinoma in transgenic mice

To investigate the role of membrane-type matrix metalloproteinase-1 (MT1-MMP) in mammary gland development and tumorigenesis, transgenic mice overexpressing MT1-MMP in mammary gland under the control of the mouse mammary tumor virus long terminal repeat-promoter were generated. The mouse mammary tumor virus/MT1-MMP transgenic mice displayed abnormalities in 82% of female mammary glands. The abnormalities were verified as lymphocytic infiltration, fibrosis, hyperplasia, alveolar structure disruption, dysplasia, and adenocarcinoma. Northern and reverse transcription-PCR analyses demonstrated that MT1-MMP mRNA was overexpressed in mammary glands exhibiting abnormalities. Western blot analysis and immunohistochemical studies have revealed that the protein expression level was also increased in these glands. In addition, the beta-casein gene as a functional epithelial cell marker was poorly expressed in the mammary glands of transgenic mice exhibiting abnormalities. Gelatin zymography showed significantly increased MMP-2 activation in these mammary glands. These results showed that overexpression of MT1-MMP induced remodeling of the extracellular matrix and tumor formation in the mammary glands of transgenic mice. Therefore, we suggest that overexpression of MT1-MMP may play a key role in development and tumorigenesis in mammary glands.

Developmental potential and transgene expression of porcine nuclear transfer embryos using somatic cells

We examined whether porcine nuclear transfer (NT) embryos carrying somatic cells have a developmental potential and NT embryos carrying transformed fibroblasts express transgenes in the preimplantation stages. In Experiment 1, different activation methods were applied to NT embryos and the development rates were examined. Relative to A23187 only or A23187/6-DMAP, electrical pulse made a significant increase in both cleavage rate (58.1+/-13.9 or 60.7+/-6.3 vs. 74.9+/-7.5%) and development rate of NT embryos to the blastocyst stage (2.2+/-2.8 or 2.2+/-1.5 vs. 11.0+/-4.1%). In Experiment 2, in vitro developmental competence of NT embryos was investigated. The developmental rate to the blastocyst stage of NT embryos (9.9+/- 2.4% for cumulus cells and 9.8+/-1.6% for fibroblast cells) was significantly lower than that (22.9+/-3.5%) of IVF-derived embryos (P<0.01). NT blastocysts derived from either cumulus (28.9+/-11.4, n = 26) or fibroblast cells (30.2+/-9.9, n = 27) showed smaller mean nuclei numbers than IVF-derived blastocysts (38.6+/-10.4, n = 62) (P<0.05). In Experiment 3, nuclear transfer of porcine fibroblasts expressing the GFP (green fluorescent protein) gene resulted in green blastocysts without losing developmental potential. These results suggest that porcine embryos reconstructed by somatic cell nuclear transfer are capable of developing to preimplantation stage. We conclude that somatic cells expressing exogenous genes can be used as nuclei donors in the production of NT-mediated transgenic pig.

Transcriptional repression, apoptosis, human disease and the functional evolution of the nuclear lamina

The number and complexity of genes encoding nuclear lamina proteins has increased during metazoan evolution. Emerging evidence reveals that transcriptional repressors such as the retinoblastoma protein, and apoptotic regulators such as CED-4, have functional and dynamic interactions with the lamina. The discovery that mutations in nuclear lamina proteins cause heritable tissue-specific diseases, including Emery-Dreifuss muscular dystrophy, is prompting a fresh look at the nuclear lamina to devise models that can account for its diverse functions and dynamics, and to understand its enigmatic structure.

A novel epigenetic control operating on Vme1+ locus leads to variegated monoallelic expression

Vme1, located near an imprinted region containing Peg1/Mest, Copg2, and Mit1/Lb9 on mouse chromosome 6, was identified and characterized to be under novel epigenetic regulations mediating nonimprinted monoallelic expression. The gene was transcribed independently from at least four promoters and alternatively spliced. Variable expression of the gene was found among individuals and was not affected by genetic backgrounds, in contrast to a relatively consistent expression of unlinked Peg3 under different genetic backgrounds. Monoallelic expression of the gene was confirmed in several tissues of hybrid F1s between a domesticus and a molossinus subspecies. The nature of monoallelic expression was different from those of its neighboring genes with respect to the allelic preference for the expression. The observed variable expression and monoallelic expression propose a mechanism that operates to variegate the Vme1 transcription acting asynchronously on parental alleles. In addition, we observed that some biallelically expressed tissues exhibited allele-specific splicing such that expression from one parental allele yields elongated splice variants, whereas the other allele is spliced into a short version. This unusual finding suggests that an epigenotype of the promoter can determine the splicing fate of the transcript.

Identification and Purification of an Intrinsic Human Muscle Myogenic Factor That Enhances Muscle Repair and Regeneration

The limited ability of damaged muscle to regenerate after gross injuries is a major clinical problem. To date, there is no effective therapeutic treatment for muscle injuries. In the present study, we have examined the ability of crude and fractionated human skeletal muscle extracts to promote myogenic cell proliferation and differentiation. It was found that the crude muscle extract could significantly stimulate BrdU incorporation in C2C12 myogenic cell line. In addition, the extract also promoted myogenic cell alignment and fusion. Using electrophoresis techniques, in conjunction with in vitro refolding technique, a protein with molecular weight of approximately 40 kDa was identified that could produce the same effects as the crude muscle exdtract. We also tested the ability of semipurified (30-50 kDa) muscle extract to promote muscle repair in adult rats. Surgical intervention was used to induce muscle damage in the tibialis anterior. The semipurified muscle extract (fraction H) was injected subcutaneously over the tibialis anterior for a period of 5 days. It was found that the damaged muscle fibers were replaced by newly regenerated muscle fibers. These newly regenerated fibers originated from the fusion of differentiated satellite cells as revealed by BrdU-labeling analysis. In contrast, the injury site of muscles treated with BSA control protein contained mainly fibroblasts.

Virulence of Vibrio parahaemolyticus isolated from cultured small abalone, Haliotis diversicolor supertexta, with withering syndrome

Outbreaks of mass mortality among cultured small abalone Haliotis diversicolor supertexta with withering syndrome occurred in May and September 1998 in Kao-Hsiung, Taiwan. Bacterial strains CH-1 and B4 were isolated from the haemolymph of the moribund small abalone using tryptic soy agar supplemented with 3% NaCl and/or thiosulphate citrate bile salt sucrose agar. These two strains were characterized and identified as Vibrio parahaemolyticus on the basis of various biochemical tests. The B4 strain and its extracellular products were virulent to small abalone with LD(50) values of 1.6 x 10(5) colony-forming units and 7.58 microg protein g-1 body weight, respectively.

Hairy cell leukemia in Hong Kong Chinese: a 12-year retrospective survey

BACKGROUND

Hairy cell leukemia (HCL) is a unique chronic B cell lymphoproliferative disease (B-LPD), with distinct clinical and pathological features, and excellent treatment response to 2-chlorodeoxyadenosine (2-CDA) and pentostatin. There have been few reports of HCL from oriental countries.

PATIENTS AND METHODS

A retrospective survey of HCL in six major hematology units in Hong Kong over a 12-year period.

RESULTS

There were 18 cases of HCL identified. Most patients presented with fever, splenomegaly and monocytopenia. Lymphadenopathy was present in three patients, and open biopsy revealed tuberculosis infection in two cases. Seven cases received interferon and 12 cases received 2-CDA. Four patients died from bronchogenic carcinoma, cerebral vascular accident, fulminant hepatitis B virus reactivation and malignant melanoma. The remaining 14 patients are in clinical remission at a median of 6 years' follow-up; two are also surviving from second malignancies (thyroid papillary carcinoma and renal cell carcinoma).

CONCLUSIONS

Parallel to the low incidence of B-LPD in Chinese, the incidence of HCL (0.035/100000 population per year) is much lower than in Western series. Other clinical features such as male dominance, clinical presentation, response to 2-CDA treatment, and association with second malignancy are similar to Western reports. However, two common complications in the Chinese population are the fulminant reactivation of hepatitis B infection and disseminated tuberculosis infection.

Screening travelers for hepatitis A antibodies: an observational cost-comparison study of vaccine use

OBJECTIVES

To measure the seroprevalence of antibodies to hepatitis A virus (anti-HAV) in a health plan population of travelers and to determine whether prevaccination screening for anti-HAV can reduce unnecessary vaccination and thus promote the most effective, economic use of hepatitis A vaccine.

DESIGN

Observational, cost-comparison study.

SETTING

Central injection clinic of a health maintenance organization medical center.

SUBJECTS

Five hundred twenty-seven adults who denied having previous hepatitis A or vaccination. MAIN OUTCOME MEASURES Subgroups with the greatest prevalence of anti-HAV seen between June 1995 and April 1996 for immunizations before traveling to nonindustrialized countries. Relative costs of their screening and immunization.

RESULTS

The presence of anti-HAV precluded the need for vaccination in 148 subjects (28.1%). The highest prevalence of anti-HAV (82.7%) was found in subjects born in nonindustrialized countries (62/75), in subjects who had previously traveled to areas of endemic hepatitis A (32.1% [135/420]), and in subjects born before 1945 (29.2% [92/315]). Costs of screening and vaccinating travelers were cheapest if prevaccination antibody sera testing was limited to subjects born in nonindustrialized countries and those born before 1945.

CONCLUSIONS

Prevaccination screening of travelers for hepatitis A can be done selectively on the basis of age and country of origin. This strategy could lead to a more economic use of the vaccine and clinic resources.

Blastocyst viability and generation of transgenic cattle following freezing of in vitro produced, DNA-injected embryos

This study examined whether the viability, determined in vitro, of DNA-injected bovine embryos produced in vitro was affected by freezing, and if the frozen embryos developed to term following transfer to recipients. In vitro fertilized zygotes were injected with the pBL1 gene and then co-cultured with mouse embryonic fibroblasts (MEF) in CR1aa medium. Embryos were prepared for cryopreservation by exposure to a 10% (v/v) glycerol solution, loaded into 0.25 ml straws and then frozen by conventional slow freezing. Thawing was by rapid warming in water (37 degrees C) and embryos were rehydrated in PBS diluents of 6%, 3% and 0% (v/v) glycerol supplemented with 0.25 M sucrose and 0.5% (w/v) BSA. In Experiment 1, blastocysts that developed from DNA-injected embryos were individually classified into three morphological groups and three stages of development prior to freezing. DNA-injected blastocysts of excellent quality at freezing showed a higher survival rate (78.8+/-10.6%) after thawing than those of good (60. 9+/-16.4%) or fair (12.5+/-5.9%) quality (P<0.05). Post-thaw survival rate, judged in vitro, increased with more advanced stage of blastocyst development at freezing (early 48.8+/-15.9%, mid 52. 1+/-12.6% and expanded 71.2+/-1.1; P<0.05). In Experiment 2, the frozen/thawed embryos were transferred to recipients to examine in vivo viability. Following transfer of one or two embryos per recipient, pregnancy rates at 60 days of gestation were 13.6% (13/96) for frozen embryos and 26.5% (43/162) for fresh embryos (P<0. 05). Of the 12 live calves born from the frozen/thawed embryos, two males (18.3%) were transgenic. None of the live-born calves derived from fresh embryos exhibited the transgene. One of transgenic bulls did not produce transgenic sperm. Three out of 23 calves (13.0%) produced from cows inseminated with semen of the other bull were transgenic, suggesting that this animal was a germ-line mosaic. These studies indicated that the viability of in vitro produced, DNA-injected bovine blastocysts was affected by freezing and by both the quality and stage of development of the embryo prior to freezing. The generation of transgenic cattle demonstrates that it is feasible to freeze DNA-injected, in vitro produced embryos.

In vitro development of reconstructed porcine oocytes after somatic cell nuclear transfer

This study was designed to examine the developmental ability of porcine embryos after somatic cell nuclear transfer. Porcine fibroblasts were isolated from fetuses at Day 40 of gestation. In vitro-matured porcine oocytes were enucleated and electrically fused with somatic cells. The reconstructed eggs were activated using electrical stimulus and cultured in vitro for 6 days. Nuclear-transferred (NT) embryos activated at a field strength of 120 V/mm (11.6 +/- 1.6%) showed a higher developmental rate as compared to the 150-V/mm group (6.5 +/- 2.3%) (P: < 0.05), but the mean cell numbers of blastocysts were similar between the two groups. Rates of blastocyst development from NT embryos electrically pulsed at different times (2, 4, and 6 h) after electrofusion were 11.6 +/- 2.9, 6.6 +/- 2.3, and 8.1 +/- 3.3%, respectively. The mean cell numbers of blastocysts developed from NT embryos were gradually decreased (30.4 +/- 10.4 > 24.6 +/- 10.1 > 16.5 +/- 7.4 per blastocyst) as exposure time (2, 4, and 6 h) of nuclei to oocyte cytoplast before activation was prolonged. There was a significant difference in the cell number between the 2- and 6-h groups (P: < 0. 05). Nuclear-transferred embryos (9.4 +/- 0.9%) had a lower developmental rate than in vitro fertilization (IVF)-derived (21.4 +/- 1.9%) or parthenogenetic embryos (22.4 +/- 7.2%) (P: < 0.01). The mean cell number (28.9 +/- 11.4) of NT-derived blastocysts was smaller than that (38.6 +/- 10.4) of IVF-derived blastocysts (P: < 0. 05) and was similar to that (29.9 +/- 12.1) of parthenogenetic embryos. Our results suggest that porcine NT eggs using somatic cells after electrical activation have developmental potential to the blastocyst stage, although with smaller cell numbers compared to IVF embryos.

The binding of Proteus mirabilis nonagglutinating fimbriae to ganglio-series asialoglycolipids and lactosyl ceramide

Proteus mirabilis is a common opportunistic Gram-negative uropathogen that infects the upper urinary tract. We have examined the role of the nonagglutinating fimbriae (NAF) of P. mirabilis in mediating bacterial adhesion to cell surface receptors. Purified NAF of P. mirabilis were demonstrated to bind to a number of glycolipids, including asialo-GM1, asialo-GM2, and lactosyl ceramide (LacCer) in solid-phase binding assays and in thin layer chromatography (TLC) overlay assays. Furthermore, preincubation of the biotinylated NAF (Bt-NAF) with anti-NAF monoclonal antibodies resulted in inhibition of NAF binding to immobilized asialo-GM1, asialo-GM2, and LacCer. In adherence assays, P. mirabilis binding to Madin-Darby canine kidney (MDCK) cells was inhibited by murine anti-asialo-GM1 monoclonal antibodies H2G10 to about 50% of the binding level in the absence of the antibody, specific for the terminal beta-galactopyranosyl residue of asialo-GM1 (Harrison et al. 1998). The results of this study suggest that NAF of P. mirabilis recognize a GalNAc beta 1-4Gal moiety present in the ganglio-series of asialoglycolipids, and that the terminal beta-galactopyranosyl-containing glycoconjugates play a role in NAF-mediated adherence of P. mirabilis to MDCK cells. Similarly to other bacteria, P. mirabilis NAF was also shown to express the LacCer specificity.

All optical quasi-steady-state photorefractive spatial solitons

We have created a one- (rather than two-) dimensional quasi-steady-state photorefractive spatial soliton induced by a laser beam instead of an applied electric field. The formation of this type of spatial soliton depends on the intensity of the self-trapped beam, which is different from quasi-steady-state spatial solitons reported in the literature. The optically induced spatial soliton can be exploited in all optical switching applications.

Neurotransmitters, neuropeptides and calcium binding proteins in developing human cerebellum: a review

Many endogenous neurochemicals that are known to have important functions in the mature central nervous system have also been found in the developing human cerebellum. Cholinergic neurons, as revealed by immunoreactivities towards choline acetyltransferase or acetylcholinesterase, appear early at 23 weeks of gestation in the cerebellar cortex and deep nuclei. Immunoreactivities gradually increase until the first postnatal month. Enkephalin is localized in the developing cerebellum, initially in the fibers of the cortex and deep nuclei at 16-20 weeks and then also in the Purkinje cells, granule cells, basket cells and Golgi cells at 23 weeks onward. Another neuropeptide, substance P, is localized mainly in the fibers of the dentate nucleus from 9 to 24 weeks but substance P immunoreactivity declines thereafter. GABA, an inhibitory neurotransmitter of the central nervous system, starts to appear at 16 weeks in the Purkinje cells, stellate cells, basket cells, mossy fibers and neurons of deep nuclei. GABA expression is gradually upregulated toward term forming networks of GABA-positive fibers and neurons. Catecholaminergic fibers and neurons are also detected in the cortex and deep nuclei at as early as 16 weeks. Calcium binding proteins, calbindin D28K and parvalbumin, make their first appearance in the cortex and deep nuclei at 14 weeks and then their expression decreases toward term, while calretinin appears later at 21 weeks but its expression increases with fetal age. The above findings suggest that many neurotransmitters, neuropeptides and calcium binding proteins (1) appear early during development of the cerebellum; (2) have specific temporal and spatial expression patterns; (3) may have functions other than those found in the mature neural systems; and (4) may be able to interact with each other during early development.

C. elegans nuclear envelope proteins emerin, MAN1, lamin, and nucleoporins reveal unique timing of nuclear envelope breakdown during mitosis

Emerin, MAN1, and LAP2 are integral membrane proteins of the vertebrate nuclear envelope. They share a 43-residue N-terminal motif termed the LEM domain. We found three putative LEM domain genes in Caenorhabditis elegans, designated emr-1, lem-2, and lem-3. We analyzed emr-l, which encodes Ce-emerin, and lem-2, which encodes Ce-MAN1. Ce-emerin and Ce-MAN1 migrate on SDS-PAGE as 17- and 52-kDa proteins, respectively. Based on their biochemical extraction properties and immunolocalization, both Ce-emerin and Ce-MAN1 are integral membrane proteins localized at the nuclear envelope. We used antibodies against Ce-MAN1, Ce-emerin, nucleoporins, and Ce-lamin to determine the timing of nuclear envelope breakdown during mitosis in C. elegans. The C. elegans nuclear envelope disassembles very late compared with vertebrates and Drosophila. The nuclear membranes remained intact everywhere except near spindle poles during metaphase and early anaphase, fully disassembling only during mid-late anaphase. Disassembly of pore complexes, and to a lesser extent the lamina, depended on embryo age: pore complexes were absent during metaphase in >30-cell embryos but existed until anaphase in 2- to 24-cell embryos. Intranuclear mRNA splicing factors disassembled after prophase. The timing of nuclear disassembly in C. elegans is novel and may reflect its evolutionary position between unicellular and more complex eukaryotes.

Potent and stage-specific action of glutathione on the development of goat early embryos in vitro

The effect of glutathione (GSH) addition on the development of 1- or 2-cell goat early embryos in vitro was examined. Embryos were collected from superovulated Korean black goat (Capra hircus aegagrus) and cultured for 6 days in synthetic oviduct fluid medium supplemented with either bovine serum albumin (BSA) or serum. Without GSH addition, almost all embryos could not develop beyond 8- to 16-cell block. However, GSH addition greatly improved in vitro development of early embryos to blastocyst stage, and its action was highly dependent on the presence and source of proteins supplemented into the culture medium. Among the protein-supplemented cultures, GSH effect was most prominent in 10% FBS-supplemented culture, in which the proportion (91%) of blastocysts developed from early embryos was much higher than that of BSA- (42-64% depending on its content) or goat serum (GS)-supplemented cultures (21%), or even than that of somatic cell-supported co-culture (60%). As well as in terms of the morphological development, mean cell number of blastocysts (185 +/- 12) developed from FBS condition was significantly higher than that of blastocysts developed from any other culture conditions and moreover comparable to that of blastocysts developed in vivo (190 +/- 9). The viability of these blastocysts was finally confirmed by their term development (6/12) from embryo transfer. To delineate action time of GSH during embryo development, GSH was treated at 1-day intervals through 6-days culture periods excepting the last day. In the GSH-treated embryos at day 3 of culture, which corresponds to the time of in vitro 8- to 16-cell block stage, the proportion of blastocyst was markedly increased up to 77% of cultured embryos and conversely that of the arrested embryos was decreased to 7%. In the embryos treated later, however, their developmental potency decreased abruptly. Therefore, these results clearly demonstrated that GSH could greatly improve the in vitro development of goat early embryos by specifically acting on the 8- to 16-cell block stage during in vitro development, suggesting that GSH may be one of the important regulators on the development of goat embryos in vivo.

Effect of intravenous omeprazole on recurrent bleeding after endoscopic treatment of bleeding peptic ulcers

BACKGROUND

After endoscopic treatment of bleeding peptic ulcers, bleeding recurs in 15 to 20 percent of patients.

METHODS

We assessed whether the use of a high dose of a proton-pump inhibitor would reduce the frequency of recurrent bleeding after endoscopic treatment of bleeding peptic ulcers. Patients with actively bleeding ulcers or ulcers with nonbleeding visible vessels were treated with an epinephrine injection followed by thermocoagulation. After hemostasis had been achieved, they were randomly assigned in a double-blind fashion to receive omeprazole (given as a bolus intravenous injection of 80 mg followed by an infusion of 8 mg per hour for 72 hours) or placebo. After the infusion, all patients were given 20 mg of omeprazole orally per day for eight weeks. The primary end point was recurrent bleeding within 30 days after endoscopy.

RESULTS

We enrolled 240 patients, 120 in each group. Bleeding recurred within 30 days in 8 patients (6.7 percent) in the omeprazole group, as compared with 27 (22.5 percent) in the placebo group (hazard ratio, 3.9; 95 percent confidence interval, 1.7 to 9.0). Most episodes of recurrent bleeding occurred during the first three days, which made up the infusion period (5 in the omeprazole group and 24 in the placebo group, P<0.001). Three patients in the omeprazole group and nine in the placebo group underwent surgery (P=0.14). Five patients (4.2 percent) in the omeprazole group and 12 (10 percent) in the placebo group died within 30 days after endoscopy (P=0.13).

CONCLUSIONS

After endoscopic treatment of bleeding peptic ulcers, a high-dose infusion of omeprazole substantially reduces the risk of recurrent bleeding.

A comparative evaluation of polytetrafluoroethylene, umbilical vein, and saphenous vein bypass grafts for femoral-popliteal above-knee revascularization: a prospective randomized Department of Veterans Affairs cooperative study

PURPOSE

Currently, the choice of a vascular prosthesis for a femoral-popliteal above-knee arterial bypass graft is left to the surgeon's preference, because the available information on comparative evaluations is inconclusive. The Department of Veterans Affairs (VA) Cooperative Study 141 was established to identify whether improved patency exists with different bypass graft materials for patients with femoral-popliteal above-knee bypass grafts.

METHODS

Between June 1983 and June 1988, 752 patients at 20 VA medical centers were randomized to receive either an externally supported polytetrafluoroethylene (PTFE; N = 265), human umbilical vein (HUV; N = 261), or saphenous vein (SV; N = 226) for an above-knee femoral-popliteal bypass graft. The indication for the bypass grafting operation was limb salvage in 67.5% of the patients. Patients were observed every 3 months for the first year and every 6 months thereafter. All patients were instructed to take aspirin (650 mg) daily for the duration of the study.Doppler-derived ankle-brachial indices (ABIs) were determined preoperatively and serially postoperatively. A bypass graft was considered to be patent when the Doppler-derived postoperative ABI remained significantly improved (more than 0.15 units higher than their preoperative value) and additional objective information, such as angiograms or operations, did not contradict these observations. Patency failure also included bypass grafts that were removed because of an infection or aneurysmal degeneration. Patency rates were compared by using the Kaplan-Meier life table analysis.

RESULTS

The cumulative assisted primary patency rates were statistically similar among the different conduit types at 2 years (SV, 81%; HUV, 70%; PTFE, 69%). After 5 years, above-knee SV bypass grafts had a significantly (P </=.01) better patency rate (73%) than HUV bypass grafts (53%), which had a significantly (P </=.01) better patency rate than PTFE bypass grafts (39%). Limb salvage was slightly worse with PTFE conduits. The number of bypass graft thromboses and major amputations within the first 30 days was highest in the HUV group.

CONCLUSION

The overall results of this prospective randomized study suggest that the SV should be considered as the bypass graft of choice for femoral-popliteal above-knee reconstruction and that, when a prosthetic bypass graft is used, an HUV should also be considered as an alternative choice to PTFE.

Effect of short interspersed element sequences on the integration and expression of a reporter gene in the preimplantation-stage mouse embryos

Based on the assumption that foreign DNA sequences may have increased chance of integration into the host genome if they are flanked by high copy-numbered genomic sequences such as SINEs (short interspersed elements), we investigated the integration frequency of Lac Z reporter gene flanked by a fused B1/B2 in an in vivo system using pronuclear microinjection technique in the mouse. The SINE-flanked DNA showed a 4-fold increased integration frequency of the reporter gene than the control DNA (63% vs. 16%). Moreover, the level of beta-galactosidase expression, estimated from the X-Gal staining intensity in transgenic embryos, was greatly higher in SINE-carrying DNA. These results suggest that the SINE sequences can serve a very useful tool in improving the efficiency of current transgenic animal technology.