Structural comparison of zebrafish Elav/Hu and their differential expressions during neurogenesis

The present communication reports the isolation and characterization of three new zebrafish elav/Hu (Kim, C.-H., Ueshima, E., Muraoka, O., Tanaka, H., Yeo, S.-Y., Huh, T.-L. and Miki, N., Zebrafish elav/HuC homologue as a very early neuronal marker. Neurosci. Lett., 216 (1996) 109-112) homologues, HuA, HuD and HuG. While HuA and HuG showed weak and ubiquitous expressions, HuD, as well as HuC, were specifically expressed in the neuronal cells. The first expression of HuD was detectable of the 10-somite stage, that is, several hours later than HuC. After 24 h of embryonic development, although HuD and HuC expressions overlapped overall, the cells expressing HuD were restricted to subsets of the HuC-positive neuronal cells in the brain and spinal cord. These differentially regulated spatial and temporal expression patterns implied distinct roles for HuC and HuD in neuronal determination and neuronal differentiation, respectively.

Effects of hydrochlorothiazide and furosemide diuretics on human bone marrow stromal osteoprogenitor cells

Thiazide diuretics have been shown to decrease bone loss and improve bone mineral density, while long-term furosemide therapy has been suggested to decrease bone mineral content. However, the direct effects of these diuretics on osteoblastic cells are not well established. Some investigators have reported direct effects of thiazides on osteoblastic cells but the results remain controversial, and there are few data about the direct effect of furosemide on osteoblastic cells. We investigated the effects of hydrochlorothiazide (HCTZ) and furosemide on proliferation, alkaline phosphatase activity, osteocalcin, and interleukin-6/interleukin-11 (IL-6/IL-11) secretion in cultured normal human bone marrow stromal osteoprogenitor cells (hBMSCs). Treatment with HCTZ or furosemide for 24 hours in the concentration range of 10(-6) to 10(-4) mol/L did not affect 3H-thymidine incorporation in hBMSCs. Cellular alkaline phosphatase activity and osteocalcin production were not changed significantly by treatment with HCTZ or furosemide (up to 10(-4) mol/L) during culture. There was also no significant difference in IL-6 and IL-11 production in hBMSCs. These results suggested that HCTZ or furosemide had no significant direct effect on proliferation, alkaline phosphatase activity, osteocalcin, and IL-6/IL-11 production in hBMSCs, and the effects of these diuretics on bone mass may be related to the indirect action on calcium balance.

Novel biphasic effect of pyrrolidine dithiocarbamate on neuronal cell viability is mediated by the differential regulation of intracellular zinc and copper ion levels, NF-kappaB, and MAP kinases

Nuclear factor kappaB (NF-kappaB) is a transcription factor involved in the expression of a wide range of genes, most of which code for proteins that play a role in immunity and inflammation. Pyrrolidine dithiocarbamate (PDTC) is a well-known inhibitor of NF-kappaB. Although its mechanism of action is conferred by its antioxidant property, other mechanisms by which PDTC can act as a prooxidant, metal chelator, and free thiol group modulator have recently been suggested. Here we report that PDTC caused a dual effect on cell viability in neuronal rat pheochromocytoma (PC12) cells, depending on its concentration. Increase of intracellular zinc and copper ion levels selectively potentiated the cytotoxic PDTC effect in a dose-dependent manner, and thiol reagents, such as glutathione and N-acetylcysteine, as well as divalent metal-chelating reagents, such as EDTA and bathocuproline disulfonic acid, blocked its cell death effect. The differential effect of PDTC on cell viability correlates well with the inhibition of NF-kappaB activities. In addition, PDTC differentially activated microtubule-associated protein (MAP) kinases, such as extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), but not p38, depending on its dose, and the coaddition of glutathione (GSH), other antioxidants, and metal ions also modulated their activities. Furthermore, stable Bcl-2 expression blocked the PDTC-induced cell death. These results suggest that the thiol groups and free zinc and copper ion levels are important for the novel biphasic PDTC effect on cell viability, which is associated with the differential activation of NF-kappaB and MAP kinases.

Prevalence and risk factors of low quantitative ultrasound values of calcaneus in Korean elderly women

Quantitative ultrasound (QUS) of bone is a new radiation-free, low-cost method that measures both bone mass and bone quality. This study was performed to establish the normative data of QUS for Korean women and to determine the prevalence and risk factors of low quantitative ultrasound values in a Korean elderly population. We studied 238 healthy women aged 20-29 years working at a hospital, and 552 women over 50 years of age living in six villages of Chung-Up district, a rural area of South Korea, using QUS measurement of bone. Broadband ultrasound attenuation and speed of sound were measured at the calcaneus, and an index combining these factors (stiffness index) was calculated. T-score was calculated from the data of young normal subjects. Of the 552 elderly women, 34.2% had T-scores between -1.0 and -2.5, and 11.8% had T-scores below -2.5. The prevalence of low quantitative ultrasound values increased with older age, longer duration following menopause, lower body mass index, younger age at menopause and smoking. In multiple logistic regression analysis, age (odds ratio = 1.40 per 5 years, P < 0.05), duration following menopause (odds ratio = 1.35 per 5 years, P < 0.05) and body mass index (odds ratio = 0.78 per quartile, P < 0.05) were independently associated with low quantitative ultrasound values. These results suggested that quantitative ultrasound measurement of the calcaneus could be a useful tool for epidemiological surveys of bone mass.

Suppression of endogenous insulin secretion by exogenous insulin in patients with insulinoma

OBJECTIVE

Previous studies have demonstrated that endogenous insulin secretion is not suppressed by exogenous insulin in patients with insulinoma. In this study we examined whether insulin secretion in insulinoma patients is suppressed by exogenous insulin during hypoglycaemia.

SUBJECTS AND METHODS

Sixteen insulinoma patients (5 men and 11 women) and 10 normal subjects were studied. Hyperinsulinaemic glucose clamp studies were performed at both euglycaemia (4.5 mmol/l glucose) and hypoglycaemia (2.5 mmol/l glucose).

RESULTS

In normal subjects, plasma C-peptide levels were suppressed by 66% during the euglycaemic hyperinsulinaemic clamps (P < 0.01). In contrast, in insulinoma patients, plasma C-peptide levels increased by 25% during the clamps (P < 0.05). In the hypoglycaemic hyperinsulinaemic clamps, plasma C-peptide levels were nearly completely (91%) suppressed in normal subjects and partially (39%) suppressed in patients with insulinoma (P < 0.01). The decrease in C-peptide levels during the hypoglycaemic clamps was > 30% in 12 (75%) of 16 insulinoma patients and > 50% in 8 (50%) patients.

CONCLUSIONS

This study demonstrated that in patients with insulinoma, insulin secretion was not suppressed by exogenous insulin during euglycaemia but was suppressed during hypoglycaemia, although the degree of suppression was less than that in normal subjects. Our results suggest that the feedback regulation of insulin secretion by exogenous insulin is partially retained in patients with insulinoma.

Testosterone 5 alpha-reductase inhibitors, menaquinone 7 produced by a Bacillus and phenazine methosulfate

Menaquinone 7 (MW: 649, C46H64O2), a natural electron acceptor for steroid ring A dehydrogenations, produced by Bacillus sp. SNU-299, was isolated as a rat prostate testosterone 5 alpha-reductase inhibitor with an IC50 value of 4.0 x 10(-5) M from the cultured broth. Phylloquinone was as active as the purified microbial metabolite with an IC50 value of 6.6 x 10(-4) M. On the basis of this evidence, the inhibitory activities of electron carriers, menadione, phenazine methosulfate, and 2,6-dichlorophenolindophenol, for rat prostate testosterone 5 alpha-reductase were tested, and the IC50 values were 3.1 x 10(-6) M, 4.9 x 10(-8) M, 8.9 x 10(-5) M, respectively. A product of the 5 alpha-reductase enzyme reaction and an electron and proton carrier, NADP+, inhibited the 5 alpha-reduction by rat prostate testosterone 5 alpha-reductase with an IC50 value of 9.2 x 10(-5) M. However, the inhibition effect of a proton carrier, carbonylcyanide-m-chlorophenylhydrazone, for rat prostate testosterone 5 alpha-reductase was substantially inactive.

Altered responsiveness to chemokines due to targeted disruption of SHIP

SHIP has been implicated in negative signaling in a number of hematopoietic cell types and is postulated to downregulate phosphatidylinositol-3-kinase- (PI-3K-) initiated events in diverse receptor signaling pathways. Because PI-3K is implicated in chemokine signaling, we investigated whether SHIP plays any role in cellular responses to chemokines. We found that a number of immature and mature hematopoietic cells from SHIP-deficient mice manifested enhanced directional migration (chemotaxis) in response to the chemokines stromal cell-derived factor-1 (SDF-1) and B-lymphocyte chemoattractant (BLC). SHIP(-/-) cells were also more active in calcium influx and actin polymerization in response to SDF-1. However, colony formation by SHIP-deficient hematopoietic progenitor cell (HPCs) was not inhibited by 13 myelosuppressive chemokines that normally inhibit proliferation of HPCs. These altered biologic activities of chemokines on SHIP-deficient cells are not caused by simple modulation of chemokine receptor expression in SHIP-deficient mice, implicating SHIP in the modulation of chemokine-induced signaling and downstream effects.

Improved estimates of effective dose equivalent using two optimal anisotropic responding dosimeters

Although the use of two dosimeters, one on the chest and the other on the back, successfully solved the underestimation problem for posterior incident photon beams, the two-dosimeter approach still has some problems-significant overestimations for lateral, overhead, and underfoot beam directions when isotropic-responding dosimeters are used for measurement. A solution to this problem is to intentionally construct the dosimeters to under-respond as the beam direction departs from normal incidence and approaches lateral, overhead, or underfoot beam directions. The objective of this study is to develop a dosimeter that does not significantly overestimate effective dose equivalent (H(E)) for lateral, overhead, and underfoot beam directions, while maintaining good performance for anterior and posterior beam directions. Several dosimeter geometries were investigated using Monte Carlo simulation to find the best geometry using aluminum oxide (Al2O3) as dosimeter attenuator material. Then, the developed Optimal Anisotropic Responding dosimeters were tested for 0.08, 0.30 and 1.00 MeV photon beams of various beam directions. The dosimeters did not overestimate H(E) by more than 80% considering all photon energies and beam directions, which is much less than the overestimation of isotropic-responding dosimeters (202%). The dosimeters also showed similar performance compared to isotropic-responding dosimeters for anterior and posterior beam directions. Finally, the dosimeters were applied to effective dose (E) and the results are compared with those of H(E).

Topical intrastromal steroid during laser in situ keratomileusis to retard interface keratitis

PURPOSE

To evaluate the effect of an intraoperative topical intrastromal steroid on the incidence and severity of nonspecific diffuse intralamellar keratitis (NSDIK).

SETTING

T.L.C. The Laser Center, Brea, California, USA.

METHODS

This prospective study included 2 cohort groups, each consisting of 105 consecutive eyes treated with laser in situ keratomileusis (LASIK) for myopia and astigmatism. Group A received the standard LASIK medication protocol and Group B, an additional drop of prednisolone sodium phosphate 1% solution on the undersurface of the cap immediately after it was reflected, prior to initiating the laser treatment. After the laser treatment was completed, the flap was repositioned; 1 minute after the steroid application, the interface was irrigated. All patients were examined postoperatively and placed in 1 of 4 categories: no interface keratitis, grade 1 (mild), grade 2 (moderate with decreased vision), or grade 3 (severe with decreased vision).

RESULTS

The incidence of NSDIK in Group A was 17.1% (18 eyes); 14 eyes (78.0%) were grade 1 and 4 (22.0%), grade 2. The incidence in Group B was 6.7% (7 eyes); all eyes were grade 1. Topical intrastromal steroid application significantly reduced the incidence and severity of NSDIK (P < .01).

CONCLUSION

We propose that intraoperative intrastromal steroid application is a safe and effective way to reduce the incidence and severity of NSDIK.

Metabolic effect of decreasing nonesterified fatty acid levels with acipimox in hyperthyroid patients

Glucose intolerance is often found in patients with hyperthyroidism, but the pathogenetic mechanisms are not fully understood. Since lipolysis is increased in hyperthyroidism, elevated plasma nonesterified fatty acids (NEFAs) may contribute to abnormal glucose metabolism in hyperthyroidism. The aim of this study was to investigate whether decreasing the plasma NEFA level with acipimox can affect glucose metabolism in hyperthyroidism. We performed an intravenous glucose tolerance test (IVGTT) with acipimox 250 mg or placebo in six untreated hyperthyroid men and six age- and body mass index (BMI)-matched controls. Fasting plasma NEFA levels were significantly higher in the hyperthyroid patients versus the controls (997.0 +/- 303.4 v290.5 +/- 169.1 micromol/L, P < .001). Plasma NEFAs decreased rapidly with acipimox treatment in both controls and hyperthyroid patients. In the controls, the glucose disappearance constant (K(G)) was not different for acipimox treatment versus placebo (2.18 +/- 0.62 v 2.42 +/- 1.00% x min(-1)). In hyperthyroid patients, acipimox treatment increased the K(G) significantly compared with placebo treatment (2.44 +/- 0.84 v 1.58 +/- 0.37% x min(-1), P < .05). Changes in K(G) values with acipimox treatment were inversely correlated with changes in plasma NEFA levels (r = -.65, P < .05). Acipimox treatment increased the acute insulin response (AIR) in hyperthyroid patients (943 +/- 381 v 698 +/- 279 microU/mL x min, P < .05), whereas it did not change the AIR in controls. Changes in the AIR with acipimox treatment correlated significantly with changes in the K(G) (r = .70, P < .05). There was a weak correlation between changes in the AIR with acipimox treatment and changes in plasma NEFA levels (r = -.55, P = .06). In summary, decreasing the plasma NEFA level with acipimox in hyperthyroid patients increases both the K(G) and AIR during an IVGTT. These findings suggest that the abnormal glucose metabolism in hyperthyroidism could be attributed, at least in part, to the increase of plasma NEFA.

TECK, an efficacious chemoattractant for human thymocytes, uses GPR-9-6/CCR9 as a specific receptor

Chemokines regulate leukocytes trafficking in normal and inflammation conditions. Thymus-seeding progenitors are made in bone marrow and migrate to the thymus where they undergo their maturation to antigen-specific T cells. Immature T cells are in thymic cortex, while mature thymocytes are in medulla. Chemokines may be important for homing of thymus-seeding progenitors, and/or differential thymocyte localization in thymus. Here we report that GPR-9-6, now called CC chemokine receptor 9 (CCR9), is a receptor for thymus-expressed chemokine, TECK. Among a panel of chemokines tested, TECK specifically induced calcium flux in CCR9-expressing cell lines. We also showed that TECK efficaciously induced chemotaxis of immature CD4(+)CD8(+) double-positive, and mature CD4(+) and CD8(+) single-positive human thymocytes. Our data suggest that TECK/CCR9 interaction may play a pivotal role in T-cell migration in the thymus.

Mapping the site on human IgG for binding of the MHC class I-related receptor, FcRn

The analysis of the pharmacokinetics of wild-type and mutated Fc fragments derived from human IgG1 indicates that Ile253, His310 and His435 play a central role in regulating serum half-life in mice. Reduced serum half-life of the recombinant, mutated fragments correlates with decreased binding to the MHC class I-related neonatal Fc receptor, FcRn. In addition, the analysis of an Fc fragment in which His435 is mutated to Arg435 demonstrates that the sequence difference at this position between human IgG1 (His435) and IgG3 (Arg435) most likely accounts for the shorter serum half-life of IgG3 relative to IgG1. In contrast to His310 and His435, the data indicate that His433 does not play a role in regulating the serum half-life of human IgG1. Thus, the interaction site of mouse FcRn on human and mouse IgG1 involves the same conserved amino acids located at the CH2-CH3 domain interface of the IgG molecule. The sequence similarities between mouse and human FcRn suggest that these studies have direct relevance to understanding the factors that govern the pharmacokinetics of therapeutic IgG.

Effects of dexamethasone on proliferation, activity, and cytokine secretion of normal human bone marrow stromal cells: possible mechanisms of glucocorticoid-induced bone loss

It is well documented that glucocorticoid excess causes bone loss, but the mechanisms of these effects remain poorly defined. To understand further the mechanisms of glucocorticoid-induced osteoporosis, we investigated the effects of glucocorticoids on bone formation and bone resorption by examining the proliferation, functional activities, and cytokine secretion of cultured human bone marrow stromal cells (hBMSC). Treatment with dexamethasone for 24 h at the concentration of 10(-8) M significantly suppressed [(3)H]thymidine incorporation and further inhibition was observed with longer treatment (8 days) or higher concentration (10(-7) M). Alkaline phosphatase activity of hBMSC was markedly stimulated with addition of dexamethasone (10(-8) M), to 191 +/- 22% (after 4 days) and 317 +/- 46% (after 7 days) of control. Dexamethasone (10(-8) M) treatment for 48 h decreased the incorporation of [(3)H]proline into collagenase-digestible protein (CDP; 43.7+/-7.9% of control) and non-collagen protein (65.2+/-8.4% of control), with a greater effect on CDP. Northern blot analysis indicated that alpha1(I)-collagen mRNA level was decreased by dexamethasone to 27.6 +/- 9.0% of the control value after 1 day of exposure, and to 55.2 +/- 6.2% after 7 days. Dexamethasone markedly suppressed basal production of interleukin (IL)-6 and IL-11 and that stimulated by parathyroid hormone (PTH), IL-1alpha, or tumour necrosis factor-alpha in a dose-dependent manner. These results suggest that the glucocorticoid-induced bone loss is derived at least in part via inhibition of bone formation, which includes the suppression of osteoblast proliferation and collagen synthesis. As both basal and PTH-stimulated production of IL-6 and IL-11 are decreased by dexamethasone, the increased bone resorption observed in glucocorticoid-induced osteopenia does not appear to be mediated by IL-6 or IL-11.

SLC/exodus2/6Ckine/TCA4 induces chemotaxis of hematopoietic progenitor cells: differential activity of ligands of CCR7, CXCR3, or CXCR4 in chemotaxis vs. suppression of progenitor proliferation

Chemokines induce chemotaxis of hematopoietic progenitor cells (HPC), and suppress their proliferation. In this study we report that SLC/ Exodus2/6Ckine/TCA4 (hereafter termed SLC) is a chemoattractant for human CD34+ HPC. SLC mainly induces preferential chemotaxis of macrophage progenitors. We examined the chemotactic activity of CXCR3 ligands on CD34+ HPC because it has been reported that SLC is a potential ligand of CXC chemokine receptor, CXCR3, in addition to a CC chemokine receptor, CCR7. It was found that the CXCR3 ligands, MIG and interferon-gamma inducible protein-10 (IP-10), unlike SLC, did not induce chemotaxis of CD34+ HPC. In this regard, CCR7 ligands (SLC and CKbeta-11), but not IP-10 and MIG, induce actin polymerization in CD34+ cells. On the other hand, CCR7 ligands and CXCR3 ligands, but not the CXCR4 ligand SDF-1, showed inhibitory activity for proliferation of myeloid progenitor cells. Our results suggest that SLC is a potential trafficking factor for HPC, and that chemokines that bind CCR7, CXCR4, and CXCR3 have differential biological activities on HPC in terms of suppression and chemotaxis.

Heart failure in Korean elderly patients — clinical features, prognosis and prognostic factors

Heart failure (HF) is very common in the elderly but there are not sufficient data about the clinical characteristics and prognostic factors of HF among the Asian elderly patients. The aim of the study was to find out the clinical characteristics, survival, and prognostic factors of HF in Korean elderly patients. Among elderly patients admitted from February 1995 to February 1998, the patients with a discharge diagnosis of HF were enrolled. Through the medical record review, the diagnosis was confirmed and clinical parameters to affect survival were identified. Total number of the subjects was 104 [age: 77+/-7 years (65-96), male:female=36:68, follow-up duration: 20+/-14 months, LVEF: 46+/-16%]. Ischemic heart disease (IHD) was the most common cause of HF (42%) followed by valvular heart disease (28%), and hypertension (20%). The 1-year survival rate was 71.3%. Advanced age [risk ratio (RR): 1.41 per 5 years of age; 95% CI: 1.11-1.80] and reduced left ventricular ejection fraction (0.69 per 10%, 0.52-0.93), poor initial functional class (2.40, 1.15-5.00), diabetes (2.79, 1.30-5.97) and past history of HF (2.37, 1.10-5.10) badly affected the survival rates. When the Cox proportional hazard model was applied for multivariate analysis, only aging (1.64 per 5 years of age, 1.19-2.28) and diabetes (4.92, 1.83-13.23) predicted poor prognosis. Twenty-seven percent of the patients had diastolic HF (LVEF>45%, LVEDD<55 mm) who had higher survival rates with marginal significance (0.35, 0.10-1.17, P=0.09).

Efficacy of conventional endoscopic disinfection and sterilization methods against Helicobacter pylori contamination

BACKGROUND

Iatrogenic transmission of Helicobacter pylori via contaminated endoscopic devices is well documented. Despite the prevalence of this infectious agent, few controlled studies have investigated the major factors that impact on reprocessing of endoscopes contaminated with H. pylori.

MATERIALS AND METHODS

An endoscope (Pentax) was contaminated with 108 cfu/ml of H. pylori in 5% bovine calf serum as standardized inoculum. The endoscope then was passed through one of eight arms (five repetitions per arm = 40 total runs), as follows: 1, recovery control (no cleaning or disinfection); 2, manual cleaning alone; 3-5, manual precleaning followed by either 10-, 20-, or 45-minute exposure to 2% glutaraldehyde and ethanol (ETOH) drying; 6, manual cleaning followed by automated reprocessing by STERIS System; 7 and 8, automated reprocessing by STERIS with and without active peracetic acid sterilant (wash-off control). Suction-biopsy channels and air-water channels were harvested for microbiological culture.

RESULTS

Control runs recovered more than 1 x 106 cfu per site, confirming the viability of the test organism and the adequacy of the biological burden for challenge. When instruments underwent manual cleaning alone (without subsequent disinfection), test organisms remained in 40% of runs at the air-water site. Manual cleaning followed by 10-, 20-, or 45-minute glutaraldehyde exposure and ETOH drying removed all test organisms from all sites in all runs (i.e., 100% disinfection). The automated STERIS system with or without active peracetic acid sterilant also removed all test organisms from all sites in all runs, as did manual cleaning followed by STERIS use.

CONCLUSION

Manual cleaning alone does not effectively remove H. pylori from an endoscope. Current joint association recommendations for minimal disinfection (manual cleaning followed by at least 20 minutes of immersion in glutaraldehyde and ETOH drying) are effective in preventing cross-transmission of H. pylori. Reprocessing using the automated STERIS system according to manufacturer's recommendations also is highly effective in sterilizing endoscopes contaminated with H. pylori.

Colonic adenocarcinoma metastatic to the thyroid gland: a case report with immunohistochemical investigation

Clinically evident metastases of carcinomas to the thyroid gland are rare, particularly from a colorectal primary tumor. We present a case of colonic adenocarcinoma metastatic to the thyroid gland with histopathologic and immunohistochemical findings. A 68-year-old woman with a history of Dukes' stage B colon carcinoma presented a mass in the thyroid gland. The tumor was confirmed to be metastatic adenocarcinoma from the colon. The immunohistochemical findings demonstrated positive staining for cytokeratin 20, low-molecular-weight cytokeratin, villin and carcinoembryonic antigen, but stains were negative for cytokeratin 7 and thyroglobulin.

Antimicrobial efficacy of endoscopic disinfection procedures: a controlled, multifactorial investigation

BACKGROUND

Adequate disinfection of endoscopes is essential to prevent environmental and patient-to-patient transmission of infectious agents, but data from controlled studies are limited. Moreover, there is controversy regarding current guidelines for disinfection. We compared the antimicrobial efficacy of several endoscopic disinfection procedures controlling for multiple factors that affect reprocessing.

METHODS

A colonoscope was contaminated with 10(8) CFU/mL of Enterococcus faecalis as a standardized inoculum. The colonoscope was passed through 1 of 16 study arms (5 reps/arm for a total of 80 runs) that were controlled for all possible combinations of the following variables: manual precleaning; 10-, 20-, or 45-minute glutaraldehyde exposure; air or ethanol drying; or automated reprocessing with peracetic acid (liquid sterilization system). Suction accessory channels and air-water channels were harvested for microbiologic culture.

RESULTS

Control runs (no cleaning or disinfection) recovered more than 5 x 10(7) CFU/mL from each sampling site. When each processing variable was isolated independent of other variables, the benefits of manual precleaning, longer soak times, and ethanol drying were apparent. When factors were combined, manual precleaning followed by 20- and 45-minute glutaraldehyde exposure and ethanol drying removed all test organisms, as did processing with the liquid sterilization system.

CONCLUSION

Although the initial cost is higher, the automated liquid sterilization system provides effective sterilization and minimizes worker exposure. In units where chemical disinfection is used, our results suggest that manual precleaning followed by at least 20-minute glutaraldehyde exposure and ethanol rinse drying are sufficient to achieve complete disinfection.

Characterization of UDP-N-acetylglucosamine:alpha-6-d-mannoside beta-1,6-N-acetylglucosaminyltransferase V from a human hepatoma cell line Hep3B

UDP-N-acetylglucosamine:alpha-6-d-mannoside beta-1, 6-N-acetylglucosaminyltransferase V (GlcNAcT-V) has been purified from cell extracts of the human hepatoma cell line, Hep3B, with 8.7% recovery. The purified enzymes had molecular masses of about 67 and 65 kDa on denaturated and natural conditions, respectively. The values of pI was 5.9. The GlcNAcT-V, when resolved by SDS-PAGE, was positive for Schiff staining, suggesting that the enzyme is glycoprotein. When GlcN,GlcN-biant-PA and UDP-GlcNAc were used as substrates, the enzyme displayed a temperature optimum of around 50 degrees C and optimum an pH of 6.5. The enzyme was stable in response to incubation from pH 4.5 to pH 10.5 at 4 degrees C for 24 h. The presence of UDP-GlcNAc and GlcN,GlcN-bi-PA protected the enzyme from heat inactivation, the extent depending upon the substrate concentration. The activity of the enzyme was stimulated by Mn2+ ion; however, it was inhibited by Fe3+. The enzyme activity was inhibited by another series of NDP-sugars including ADP-, CDP-, GDP-, and TDP-GlcNAc. Studies on the activity of the enzyme toward a variety of pyridylaminated sugars showed that the enzyme is most active toward biantennary (GlcN,GlcN-bi-PA) sugars. The enzymes had apparent Km values of 1.28 and 5.8 mM for GlcN,GlcN-bi-PA and UDP-GlcNAc, respectively. In order to isolate the GlcNAcT-V gene, PCR primers of GNN-1 and GNN-8 were designed and the amplified PCR product carrying the gene was cloned and sequenced. Nucleotide sequence analysis showed a 2220-bp open reading frame encoding a 740-amino-acid protein. This was almost same as the previously reported human sequences, except for some sequence differences in three amino acids. The three amino acid changes were as follows: 375V --> L, 555T --> R, and 592A --> G. These studies represent the detailed characterization of a purified GlcNAcT-V from human hepatoma cell Hep3B.

Regulation of hematopoiesis in a sea of chemokine family members with a plethora of redundant activities

The field of chemokine biology is a rapidly advancing one, with over 50 chemokines identified that mediate their effects through one or more of 16 different chemokine receptors. Chemokines, originally identified as chemotactic cytokines, manifest a number of functions, including modulation of blood cell production at the level of hematopoietic stem/progenitor cells and the directed movement of these early blood cells. This report reviews chemokines and chemokine/receptor activities mainly in the context of hematopoietic cell regulation and the numerous chemokines that manifest suppressive activity on proliferation of stem/progenitor cells. This is contrasted with the specificity of only a few chemokines for the chemotaxis of these early cells. The large number of chemokines with suppressive activity is hypothesized to reflect the different cell, tissue, and organ sites of production of these chemokines and the need to control stem/progenitor cell proliferation in different organ sites throughout the body.

Pyrithione, a zinc ionophore, inhibits NF-kappaB activation

Pyrrolidine dithiocarbamate (PDTC) suppresses NF-kappaB activity and exhibits cytotoxic effects in bovine cerebral endothelial cells (BCECs), and we have previously reported that these PDTC effects were accompanied by an increase in intracellular zinc levels. To further explore the role of zinc in the modulation of NF-kappaB activation, we studied the effect of pyrithione, a zinc ionophore, on NF-kappaB activation in BCECs. Pyrithione inhibited NF-kappaB activity in a time- and dose-dependent manner. Ca-EDTA, but not Zn-EDTA, prevented pyrithione inhibition of NF-kappaB activity. Pyrithione increased the intracellular zinc level within 15 min. This effect was also abolished by Ca-EDTA, but not by Zn-EDTA. The potency of pyrithione on NF-kappaB inhibition and zinc influx was approximately one order of magnitude more potent than PDTC. These findings establish the regulatory role of intracellular zinc levels on NF-kappaB activity in BCECs.

Symptomatic sacral extradural arachnoid cyst associated with lumbar intradural arachnoid cyst

A case of sacral extradural arachnoid cyst associated with lumbar intradural arachnoid cyst in a 35-year-old male is reported. The patient presented with a history of severe sacrococcygeal pain, constipation, and dysuria for several months. Computed tomographic (CT) myelograms and magnetic resonance imaging (MRI) scans showed a huge sacral cyst without neural components. A favorable outcome could be achieved by decompression of the cyst, obliteration of the fistulous channel between the cyst and the thecal sac, and fenestration of the arachnoid cyst into the subarachnoid space. The relevant literatures are also reviewed.

A role of actin filament in synaptic transmission and long-term potentiation

The role of actin filaments in synaptic function has been studied in the CA1 region of the rat hippocampal slice. Bath application (2 hr) of the actin polymerization inhibitor latrunculin B did not substantially affect the shape of dendrites or spines. However, this and other drugs that affect actin did affect synaptic function. Bath-applied latrunculin B reduced the synaptic response. Several lines of evidence indicate that a component of this effect is presynaptic. To specifically test for a postsynaptic role for actin, latrunculin B or phalloidin, an actin filament stabilizer, was perfused into the postsynaptic neuron. The magnitude of long-term potentiation (LTP) was decreased at times when baseline transmission was not yet affected. Longer applications produced a decrease in baseline AMPA receptor (AMPAR)-mediated transmission. The magnitude of the NMDA receptor-mediated transmission was unaffected, indicating a specific effect on the AMPAR. These results suggest that postsynaptic actin filaments are involved in a dynamic process required to maintain AMPAR-mediated transmission and to enhance it during LTP.

Developmental patterns of GalBeta1,3(4)GlcNAc alpha2,3-sialyltransferase (ST3Gal III) expression in the mouse: in situ hybridization using DIG-labeled RNA probes

Sialic acids are key determinants for biological processes, such as cell-cell interaction and differentiation. Sialyltransferases contribute to the diversity in carbohydrate structure through their attachment of sialic acid in various terminal positions on glycolipid and glycoprotein (N-linked and O-linked) carbohydrate groups. Galbeta 1,3(4)GlcNAc alpha2,3-sialyltransferase (ST3Gal III) is involved in the biosynthesis of sLe(x)and sLe(a) known as selectin ligands and tumor-associated carbohydrate structures. The appearance and differential distribution of ST3Gal III mRNA during mice embryogenesis [embryonic (E) days; E9, E11, E13, E15] were investigated by in situ hybridization with digoxigenin-labeled RNA probes coupled with alkaline phosphatase detection. On E9, all tissues were positive for ST3Gal III mRNA expression, whereas ST3Gal III mRNA on E11 was not detected throughout all tissues. On E13, ST3Gal III mRNA was expressed in different manner in various tissues. In this stage, ST3Gal III mRNA was positive only in the liver, pancreas and bladder. On E15, specific signal for ST3Gal III was detected in the liver, lung and forebrain. These results indicate that ST3GAI III is differently expressed at developmental stages of mice embryo, and this may be importantly related with regulation of organogenesis in mice.