Activation of mouse B lymphocyte by proteins containing hexahistidine

Many recombinant proteins are produced as a fusion protein tagging hexahistidine, which has been used for studying their biological function both in vitro and in vivo. Unexpectedly, we observed activation of BALB/c mouse splenocytes when treated with hexahistidine-tagged recombinant proteins. This activation was hexahistidine-specific since the anti-pentahistidine antibody completely neutralized the effect, and the bovine serum albumin conjugated with the hexahistidine peptides also showed a similar activation effect. The B cells seemed to be the activated splenocytes, since the cell population stained with the anti-immunoglobulin antibody and anti-CD80 antibody was increased after the treatment. However, the activation signal by hexahistidine was insufficient to fully differentiate the B lymphocytes. This result suggests that caution must be taken in the use of hexahistidine-tagged recombinant proteins, due to their nonspecific activation of B lymphocyte.

High glucose stimulates Ca2+ uptake via cAMP and PLC/PKC pathways in primary cultured renal proximal tubule cells

Alteration of [Ca2+]i by hyperglycemia is implicated in the pathogenesis of diabetic nephropathy. However, the effect of high glucose on Ca2+ regulation in proximal tubule cells is not known. Thus, we examined the mechanisms by which high glucose regulates Ca2+ uptake in primary cultured rabbit renal proximal tubule cells. Glucose increased the Ca2+ uptake in a time- and dose-dependent manner. A stimulatory effect of high glucose on Ca2+ uptake is predominantly observed using 25 mM glucose (high glucose) after 1 h, while 25 mM glucose did not affect cell viability and lactate dehydrogenase release. However, 25 mM mannitol and L-glucose did not affect Ca2+ uptake as compared with controls. Nifedipine and methoxyverapamil (L-type Ca2+ channel blockers) blocked high-glucose-induced stimulation of Ca2+ uptake. High-glucose-induced stimulation of Ca2+ uptake was blocked by pertussis toxin, SQ-22536 (adenylate cyclase inhibitor), myristoylated amide 14-22 (protein kinase A inhibitor), neomycin and U-73122 (phospholipase C inhibitors), and staurosporine and bisindolylmaleimide I (protein kinase C inhibitors). In addition, KN-62 (a Ca2+/calmodulin-dependent protein kinase II inhibitor) and W-7 (a Ca2+/calmodulin antagonist) blocked high-glucose-induced stimulation of Ca2+ uptake. In conclusion, high glucose stimulates the Ca2+ uptake through L-type Ca2+ channels via G-protein-coupled adenylate cyclase/cAMP and phospholipase C/protein kinase C pathways.

Diptericin-like protein: an immune response gene regulated by the anti-bacterial gene induction pathway in Drosophila

Insects produce various anti-microbial peptides in response to injury and infection. In Drosophila, diptericin has previously been studied as an anti-bacterial immune response gene. Here, we report the cloning of the diptericin-like protein (dptlp) gene as a paralog of Drosophila diptericin. By comparison of their sequences, we found that the dptlp gene has all of the functional domains conserved in the diptericin gene and other anti-bacterial proteins. The dptlp gene was rapidly induced by bacterial infections and showed different time-dependent gene expression patterns from those of diptericin. Like diptericin, dptlp was specifically produced from the fat body, and its expression was strictly dependent on bacterial infections. In addition, the dptlp gene expression was almost completely abolished in the imd mutant, which implicates that its expression is regulated by the anti-bacterial arm of the Drosophila innate immune regulatory pathways. In support of this, we found GATA, interferon consensus responding element, and kappa B binding sites, which is known to be important for the proper expression of anti-bacterial genes, in the proximal promoter region of the dptlp gene. Taken together, our findings support that dptlp is a novel anti-bacterial peptide whose expression is regulated by the anti-bacterial immune response mechanism.

Induction of haptoglobin by all-trans retinoic acid in THP-1 human monocytic cell line

Haptoglobin (Hp) is one of the acute-phase proteins and is mainly synthesized in the liver. During our study on the differentiation of leukemia cells, we have found that Hp is synthesized in human monocytic cells by all-trans retinoic acid (ATRA). The synthesis of Hp by ATRA is induced in a dose- and time-dependent manner. Hp cDNA cloned from ATRA-treated THP-1 cells corresponds to the Hp alpha 2(FS)-beta form. Whereas ATRA acted as a strong inducer in THP-1 cells, IL-1 beta, TNF-alpha, IL-6, and LPS had little effect on Hp gene expression in these cells. These findings suggest that THP-1 cells express the Hp gene through a signal pathway different from hepatocytes, and that ATRA is a potent Hp-inducer in these cells.

Serum after partial hepatectomy stimulates iNOS gene transcription via downstream NF-kappa B site

It has been known that the expression of inducible nitric oxide synthase (iNOS) is up-regulated during hepatic regeneration. The present study characterized the molecular mechanisms involved in the transcriptional activation of iNOS gene by using the serum after partial hepatectomy (post-PH serum) in vitro. The post-PH serum rapidly induced iNOS mRNA expression, which was blocked by anti-tumor necrosis factor-alpha (TNF-alpha) antibody in BNL CL.2 cells, murine embryonic liver cell line. In addition, EMSAs using a NF-kappa B-specific oligomer showed that the up-regulated iNOS mRNA expression in cells treated with post-PH serum correlated with transient activation of NF-kappa B complex (p50/p65 heterodimer). Transient transfection of BNL CL.2 cells with iNOS promoter linked to a CAT reporter gene showed the transcriptional activation of iNOS promoter by post-PH serum. Furthermore, site-directed mutational analysis of the two NF-kappa B sites individually or in combination revealed that iNOS expression by post-PH serum is regulated by the downstream NF-kappa B site, but not by upstream NF-kappa B site. Taken together, these results suggest that the downstream NF-kappa B site acts as an essential component for the iNOS expression by post-PH serum during hepatic regeneration.

Prognostic significance of cerebral metabolic abnormalities in patients with congestive heart failure

BACKGROUND

Cerebral metabolic abnormalities were proposed as a potential marker of disease severity in congestive heart failure (CHF), but their prognostic significance remains uncertain.

METHODS AND RESULTS

We investigated the prognostic value of cerebral metabolic abnormalities in 130 consecutive patients with advanced CHF (100 men aged 42.6+/-11.9 years; left ventricular ejection fraction, 22.2+/-6.2%). Proton magnetic resonance spectroscopy data were obtained from localized regions ( approximately 8 mL) of the occipital gray matter and the parietal white matter. The primary end point was the occurrence of death after the proton magnetic resonance spectroscopy. During follow-up (18.5+/-14.4 months), 21 patients died and 15 underwent urgent heart transplantation. In the Cox proportional model, occipital metabolites (N-acetylaspartate, creatine, choline, and myoinositol), parietal N-acetylaspartate level, and the duration of CHF symptoms (>12 months) were validated as univariate predictors of death. In multivariate Cox analyses, however, the occipital N-acetylaspartate level was an independent predictor of death (hazard ratio, 0.52; 95% CI, 0.41 to 0.67; P<0.001). An analysis with respect to the combined end point of death or urgent transplantation showed similar results. The best cutoff value (9.0 mmol/kg) for occipital N-acetylaspartate level had 75% sensitivity and 67% specificity to predict mortality.

CONCLUSIONS

The occipital N-acetylaspartate level is a powerful and independent predictor of CHF mortality, suggesting that cerebral metabolic abnormalities may be used as a new prognostic marker in the assessment of patients with CHF.

Gene profile of replicative senescence is different from progeria or elderly donor

In vitro cellular senescence of human diploid fibroblast has been a good model for aging research, which shows similar phenotypes to in vivo aging. Gene expression profiling would provide an insight to understand the mechanism of senescence. Using cDNA microarray containing 384 known genes, we compared the expression profiles of three different types of aging models: replicative senescence, fibroblasts from progeria or from elderly donor. Although all of them showed senescence phenotypes, distinct sets of genes were altered in each group. Pairwise plots or cluster analysis of activation fold of gene expression revealed closer relationships between fibroblasts from progeria or from old individual, but not between replicative senescence fibroblasts and either models. Differential expression pattern of several genes were confirmed by RT-PCR. We suggest that the replicative senescence model might behave differently to other types of aging models due to the distinct gene expression.

Peritoneal accumulation of advanced glycosylation end-products in diabetic rats on dialysis with icodextrin

OBJECTIVE

To evaluate and compare the effects of glucose-based solutions to those of icodextrin with respect to peritoneal transport characteristics and formation of advanced glycosylation end-products (AGEs) in the peritoneal membrane in the diabetic rat model of peritoneal dialysis (PD).

STUDY DESIGN

Thirty-three male Sprague-Dawley rats weighing between 275 - 300 g were divided into 5 groups: group C (n = 6), control rats with catheter but not dialyzed; group D (n = 5), diabetic rats with catheter but not dialyzed; group G (n = 7), diabetic rats dialyzed with standard 2.5% glucose solution for daytime exchanges and 4.25% glucose solution for the overnight exchange; group H (n = 8), diabetic rats dialyzed with standard 2.5% glucose solution for daytime exchanges and 7.5% icodextrin solution for overnight exchanges; group I (n = 7), diabetic rats dialyzed with 7.5% icodextrin solution for all exchanges. Dialysis exchanges were performed three times daily with an instillation volume of 25 mL per exchange for a period of 12 weeks. Tissue sections were stained using a monoclonal anti-AGE antibody. One-hour peritoneal equilibration tests (PET) were performed every 4 weeks for comparison of transport characteristics.

RESULTS

The level of immunostaining was lowest in group C and highest in group G. Significant differences were seen between group C and groups G, H, and I (p < 0.001, p = 0.001, and p< 0.05 respectively). Significant differences were also found between group G and groups D and I (p < 0.05 and p < 0.05 respectively). Over time, glucose concentration at the end of an exchange versus concentration at instillation (D/D0 glucose) decreased and dialysate-to-plasma ratio (D/P) of urea increased. Significant differences were found between groups C and H for D/D0 glucose (0.40+/-0.01 vs 0.35+/-0.01, p < 0.05); and between groups C and H for D/P urea (0.87+/-0.03 vs 0.97+/-0.02, p < 0.05).

CONCLUSIONS

These results suggest that AGE formation is lower with the use of peritoneal dialysis solution containing icodextrin than with glucose-based solutions. We conclude that the use of icodextrin may be helpful in slowing the deterioration of the peritoneal membrane, prolonging its use for dialysis.

Downregulated Expression of Integrin α6 by Transforming Growth Factor-β1 on Lens Epithelial Cells in Vitro

Integrins represent the main cell surface receptors that mediate cell-matrix and cell-cell interactions. They play critical roles in adhesion, migration, morphogenesis, and the differentiation of several cell types. Previous studies have demonstrated that members of the fibroblast growth factor (FGF)-2, transforming growth factor (TGF)-beta(1), and insulin growth factor (IGF)-1 play important roles in lens biology. In particularly, TGF-beta(1) appears to play a key role in extracellular matrix production, cell proliferation, and cell differentiation of lens epithelial cells. In this study we investigated the effects of FGF-2, TGF-beta(1), and IGF-1 on the modulation of integrin receptors using lens epithelial cell lines (HLE B-3 and alphaTN-4) and lens explants. We found that the expression of integrin alpha6 is downregulated by TGF-beta(1), but is not responsive to FGF-2 or IGF-1. The promoter activity of the integrin alpha6 gene decreased upon TGF-beta(1) treatment in a transient transfection assay, and flow cytometric analysis demonstrated the reduced expression of integrin alpha6 by TGF-beta(1), whereas significant changes were not observed in the level of integrin alpha6 after the addition of FGF-2. These findings suggest that the reduced expression of integrin alpha6 caused by TGF-beta(1) might play a role in the activation of the cell cycle genes required during the fiber differentiation of the lens.

Smad3 and Smad4 mediate transforming growth factor-beta1-induced IgA expression in murine B lymphocytes

Transforming growth factor (TGF)-beta1 is well established as a critical IgA isotype switching factor and Smad molecules have been reported to act as transducers and transcriptional factors in the expression of TGF-beta1-targeted genes. We examined the involvement of Smad proteins in TGF-beta1-induced IgA expression. First, we found that TGF-beta1 significantly increases endogenous germ-line (GL) alpha transcripts by LPS-stimulated CH12.LX.4933 (mu(+)) B lymphoma cells. To investigate its signaling mechanisms, the lymphoma cell line was transfected with pFL3 that contains the TGF-beta-responsive element of the GLalpha promoter, and stimulated with TGF-beta1. Similar to endogenous GLalpha transcripts, TGF-beta1 induces GLalpha promoter activity and overexpression of Smad3 markedly enhances the promoter activity. This activity is further augmented by cotransfected Smad4. On the other hand, Smad7 substantially abrogates the synergistic effect of Smad3/4 onGLalpha promoter activity. In addition, overexpression of Smad3/4 enhances TGF-beta1-induced endogenous GLalpha transcripts in normal spleen B cells. Finally, in the presence of TGF-beta1, overexpression of Smad3/4 selectively increases both surface IgA expression and IgA production. The results from the present study indicate that Smad3, Smad4, and Smad7, at least in part, serve as mediators linking TGF-beta1 to transcriptional regulation of IgA switching related gene and regulation of IgA class switching.

Original sagittal split osteotomy revisited for mandibular distraction

INTRODUCTION

A malformed mandible and an abnormally positioned mandibular foramen make it difficult to plan an ideal osteotomy line for mandibular distraction. In addition, there have been reports of such complications as nonunion, damage and stretch injury of the inferior alveolar nerve and tooth germ damage when conventional osteotomy or corticotomy are used for mandibular distraction. The authors utilized the original sagittal split ramus osteotomy for mandibular distraction.

PATIENTS AND METHODS

Five patients (three unilateral hemifacial microsomia, one bilateral hemifacial microsomia, and one mandibular retrusion) were included in this study of distraction osteogenesis using the sagittal split ramus osteotomy. Extraoral distraction devices were applied to the first four patients. An intraoral device with mono-cortical screw fixation was used for the fifth patient.

RESULT

In all five cases, the results of the distraction were satisfactory. Complications (as listed) of conventional osteotomy when used for distraction were avoided. Satisfactory results were achieved and these were also well maintained postoperatively (mean follow up: 36 months).

CONCLUSION

The authors believe that sagittal osteotomy for mandibular distraction osteogenesis makes it possible, to avoid injury to the inferior alveolar nerve during operation and stretching injury during distraction and to prevent tooth germ injury. It is also possible to diversify the osteotomy line for various force vectors to enlarge the bony contact surface area. Therefore, we suggest that sagittal split ramus osteotomy should be used as a preferred modification of osteotomy for mandibular distraction.

Aberrant Expression of Cyclin D1 Is Associated with Poor Prognosis in Early Stage Cervical Cancer of the Uterus

OBJECTIVE

Many investigators have studied the expression of G1 phase regulatory protein in uterine cervical cancer. However, it is unclear which step of the genetic expression participates in cyclin D1 expression and what its prognostic meaning is. The aims of this study were to evaluate the regulatory level of cyclin D1 expression and the relationship between the expression of cyclin D1 and its inhibitor, p21WAF1/CIP1, and to evaluate their impact on the prognosis of early stage cervical cancer.

METHODS

The presence of cyclin D1 mRNA was studied using Northern blot in 6 normal cervices and 7 invasive cervical cancer specimens. Western blot was used to detect the cyclin D1 protein in 8 normal cervices and 8 invasive cancer specimens. Thirty-two cases of FIGO stage Ib-IIa cervical cancers (28 squamous cell carcinomas, 3 adenocarcinomas, 1 adenosquamous cell carcinoma), 31 cases of cervical intraepithelial neoplasia 3 (CIN 3), and 28 normal cervices were stained for cyclin D1 and p21(WAF1/CIP1) using monoclonal antibody. Statistical analysis was performed to assess the differences in expression and their prognostic significance. RESULTS. Cyclin D1 mRNA was found to be underexpressed in cervical cancer. Western blot also revealed underexpression of cyclin D1 protein in cervical cancer compared to normal controls. Positive immunohistochemical staining of cyclin D1 was noted in 28/28 (100%) of the normal controls, 1/31 (3%) cases of CIN 3, and 9/32 (28%) cases of invasive cancer. The number of positively stained specimens was lower than that of normal controls in CIN 3 and cervical cancer specimens (P = 0.005). Fifteen of 28 (54%) normal controls, 15/31 cases (48%) of CIN 3, and 27/32 cases (84%) of invasive cancer were proved positive for p21WAF1/CIP1 immunohistochemistry. p21WAF1/CIP1 was more highly expressed in cervical cancer than in that of either normal controls or CIN specimens (P = 0.001). Positive immunostaining of cyclin D1 and p21WAF1/CIP1 was not related to high-risk factors (pelvic lymph node metastasis, deep cervical stromal invasion, parametrial invasion, large tumor size, and unusual histologic type) and human papilloma virus infection. Positive cyclin D1 immunostaining was associated with decreased disease-free survival and a lower overall survival (P = 0.0175 and 0.0189, respectively). On multivariate analysis, positive cyclin D1 expression was a significant prognostic variable for recurrence (P = 0.0004).

CONCLUSION

Underexpression of cyclin D1 was regulated at the level of transcription in cervical cancer. Although cyclin D1 was underexpressed in cervical neoplasias, it was more frequently expressed in malignant lesions. p21WAF1/CIP1 was more highly expressed in cervical cancers than in either normal cervices or CIN 3 specimens. Unfavorable prognoses were associated with cyclin D1 expression, and not with the expression of its inhibitor, p21WAF1/CIP1.We conclude that immunohistochemical assessment of cyclin D1 can be a useful molecular marker for predicting prognosis in early stage cervical cancer of the uterus.

Impact of splenectomy for lymph node dissection on long-term surgical outcome in gastric cancer

BACKGROUND

In the treatment of gastric cancer, splenectomy is performed for effective lymph node dissection around the splenic artery and splenic hilum. The purpose of this study was to clarify the long-term outcome of splenectomy in the treatment of gastric cancer.

METHODS

The effect of splenectomy on recurrence and prognosis was examined in a retrospective analysis of 665 patients who had undergone curative total gastrectomy for gastric carcinoma from 1987 to 1996. The risk factors associated with recurrence and prognosis were investigated by univariate and multivariate analysis.

RESULTS

The splenectomy group showed more advanced lesions and a higher recurrence rate than the spleen-preserved group. However, after adjusting for the TNM (tumor, node, metastasis) stage, there was no significant difference in recurrence rate and pattern between the two groups. Logistic regression analysis revealed that gross type, serosal invasion, and nodal metastasis were independent risk factors for recurrence while splenectomy was not. When comparing patients with the same TNM (tumor, node, metastasis) stages, no significant difference in the 5-year survival rates was apparent. Multivariate analysis demonstrated that age, serosal invasion, and nodal metastasis were independent prognostic factors whereas splenectomy was not.

CONCLUSIONS

These data suggest that splenectomy for lymph node dissection in gastric cancer is not effective regarding long-term patient prognosis.

Comparison of the short-term clinical results of silicone and acrylic intraocular lens in patients with diabetes mellitus

In order to compare the clinical results of silicone intraocular lenses (IOLs) and acrylic IOLs in patients with diabetes mellitus (DM), we reviewed the records of 69 diabetic patients (79 eyes--40 eyes; silicone IOLs, 39 eyes; acrylic IOLs) who had undergone phacoemulsifications and posterior chamber intraocular lens (PCI) implantations between January 1994 and January 1999. Postoperative ocular examinations included measurements of uncorrected and best corrected visual acuity tests and recording any complication one day, one week and two months after surgery. There was no statistically significant difference in visual acuity between the eyes with silicone IOLs and those with acrylic IOLs. Additionally, there was no difference in visual acuity according to the method of blood sugar level control. The rate of posterior capsular opacity (PCO) was significantly lower in the patients with acrylic IOLs than in those with silicone IOLs (p<0.05). These results suggest that there is no difference in visual outcome between acrylic IOLs and silicone IOLs in patients with DM. However in view of the lower rates of PCO with acrylic IOLs, they may be a better choice for eyes in diabetic patients.

Hepatopulmonary syndrome in poorly compensated postnecrotic liver cirrhosis by hepatitis B virus in Korea

BACKGROUND

Hepatopulmonary syndrome (HPS) refers to the association of hypoxemia, intrapulmonary shunting and chronic liver disease. But there is no clear data about the prevalence of HPS in postnecrotic liver cirrhosis by hepatitis B virus (HBV), the most common cause of liver disease in Korea. The aim of this study was to investigate the prevalence of HPS in poorly compensated postnecrotic liver cirrhosis by HBV, and the correlation of the hepatopulmonary syndrome with clinical aspects of postnecrotic liver cirrhosis by HBV.

METHODS

Thirty-five patients underwent pulmonary function test, arterial blood gas analysis and contrast-enhanced echocardiography. All patients were diagnosed as HBV-induced Child class C liver cirrhosis and had no evidence of intrinsic cardiopulmonary disease.

RESULTS

Intrapulmonary shunt was detected in 6/35 (17.1%) by contrast-enhanced echocardiography. Two of six patients with intrahepatic shunts had significant hypoxemia (PaO2 < 70 mmHg) and four showed increased alveolar-arterial oxygen gradient over 20 mmHg. Only cyanosis could reliably distinguish between shunt positive and negative patients.

CONCLUSIONS

The prevalence of intrapulmonary shunt in poorly compensated postnecrotic liver cirrhosis by HBV was 17.1% and the frequency of hepatopulmonary syndrome was relatively low (5.7%). 'Subclinical' hepatopulmonary syndrome (echocardiographically positive intrapulmonary shunt but without profound hypoxemia) exists in 11.4% of cases with poorly compensated postnecrotic liver cirrhosis by HBV. Cyanosis is the only reliable clinical indicator of HPS of HBV-induced poorly compensated liver cirrhosis. Further studies are required to determine if the prevalence and clinical manifestations of HPS varies with etiology or with geographical and racial differences.

Interferon alfa down-regulates CD81 in patients with chronic hepatitis C

CD81 protein has been shown to bind hepatitis C virus (HCV) envelope 2 (E2) glycoprotein in vitro and may act as a (co)receptor for HCV. Regulation of CD81 expression by interferon alfa (IFN-alpha) and ribavirin could thereby affect the response to antiviral therapy. In the present study, the effects of IFN-alpha and ribavirin on CD81 protein and CD81 mRNA were assessed in peripheral blood lymphocytes (PBL) and isolated human hepatocytes by fluorescence-activated cell sorter (FACS) analysis and real-time polymerase chain reaction (PCR), respectively. In addition, regulation of CD81 in PBL was investigated in 10 patients treated with combination therapy. Incubation with IFN-alpha (50 U/mL) down-regulated total CD81 in PBL (81.7 +/- 11.6% of control; P =.003) and in isolated human hepatocytes (91.6 +/- 8.1% of control; P =.034). Incubation with IFN-alpha with and without ribavirin (2.2 microg/mL) significantly reduced cell surface-associated CD81 protein (83.9 +/- 10.3% of control; P =.003). PBL of untreated patients chronically infected with HCV had significantly higher levels of total CD81 protein compared with PBL obtained from healthy donors (631.1 +/- 93.3 vs. 538.9 +/- 95.2 relative fluorescence units [RFU]; P =.030). Pretreatment cell surface-associated CD81 protein was lower in patients infected with genotype HCV-3 than those infected with HCV-1 (111.8 +/- 15.0 vs. 162.0 +/- 41.3 RFU; P =.019). Furthermore, cell surface-associated CD81 protein was lower 4 weeks after initiation of therapy in patients with an initial virologic response compared with initial virologic nonresponders (110.5 +/- 8.5 vs. 139.8 +/- 27.5 RFU; P =.057). In conclusion, IFN-alpha and ribavirin regulate CD81 expression in vitro and in vivo. CD81 expression correlates with HCV genotype and initial virologic response in patients with chronic hepatitis C.

Rapid sexing of preimplantation bovine embryo using consecutive and multiplex polymerase chain reaction (PCR) with biopsied single blastomere

The objective of this study was to establish a rapid and reliable PCR method for the sexing of 8- to 16-cell stage bovine embryos. The BOV97M and bovine 1.715 satellite DNA sequences were selected for amplification of male- and bovine-specific DNA, respectively. But the unequal number of copies of these two repetitive sequences required some modification of the multiplex PCR method. In consecutive and multiplex PCR, the first 10 PCR cycles were done with male-specific primer followed by an additional 23 cycles with bovine-specific primer. In this PCR method, the appearance of male- and bovine-specific bands was independent of the DNA concentration. This PCR method was applied successfully using groups of 8, 4, 2, and 1 blastomeres dissociated from the embryos, and the sexing efficiency was 100.0, 96.3, 94.3 and 92.1%, respectively. The coincident rate of sex determination between biopsied single blastomere and matched blastocyst was 90.0%. Therefore the developmental potential from 8- to 16-cell stage embryos to the blastocyst stage was not significantly different (P>0.2) for intact embryo (42.3%) than for demi-embryos (53.8%), suggesting that trauma to the demi-embryo caused by single-blastomere aspiration using a bevelled micropipette was very small. In conclusion, we developed a rapid (within 2 hours) and effective PCR method for the sexing of 8- to 16-cell stage bovine embryos using a single blastomere.

Molecular defects underlying the Kell null phenotype

Expression of the Kell blood group system is dependent on two proteins, Kell and XK, that are linked by a single disulfide bond. Kell, a type II membrane glycoprotein, is a zinc endopeptidase, while XK, which has 10 transmembrane domains, is a putative membrane transporter. A rare phenotype termed Kell null (Ko) is characterized by the absence of Kell protein and Kell antigens from the red cell membrane and diminished amounts of XK protein. We determined the molecular basis of eight unrelated persons with Ko phenotypes by sequencing the coding and the intron-exon splice regions of KEL and, in some cases, analysis of mRNA transcripts and expression of mutants on the cell surface of transfected cells. Six subjects were homozygous: four with premature stop codons, one with a 5' splice site mutation, G to A, in intron 3, and one with an amino acid substitution (S676N) in exon 18. Two Ko persons with premature stop codons had identical mutations in exon 4 (R128Stop), another had a different mutation in exon 4 (C83Stop), and the fourth had a stop codon in exon 9 (Q348Stop). Two Ko persons were heterozygous for two mutations. One had a 5' splice site mutation (G to A) in intron 3 of one allele that caused aberrant splicing and exon skipping, and the other allele had an amino acid substitution in exon 10 (S363N). The other heterozygote had the same amino acid substitution in exon 10 (S363N) in one allele and a premature stop codon in exon 6 (R192Stop) in the other allele. The S363N and S676N mutants, expressed in 293T cells, were retained in a pre-Golgi compartment and were not transported to the cell surface, indicating that these mutations inhibit trafficking. We conclude that several different molecular defects cause the Kell null phenotype.

Different frequencies of electroacupuncture modified the cellular activity of serotonergic neurons in brainstem

In this study, we evaluated whether different frequencies of electroacupuncture (EA) modified the activities of serotonergic neurons in the dorsal raphe (DR) and raphe magnus (RMg) using double labeling immunohistochemistry for Fos and serotonin. The results demonstrated that both high and low frequency EA increased the colocalization between Fos and serotonin in the DR, not in RMg as compared with anesthesia control. In addition, high frequency EA more potently increased the serotonergic activity in the DR rather than low frequency EA, suggesting that serotonergic pathway from the DR plays an important role in the high frequency EA analgesia.

Drosophila phosphoinositide-dependent kinase-1 regulates apoptosis and growth via the phosphoinositide 3-kinase-dependent signaling pathway

Phosphoinositide-dependent kinase-1 (PDK-1) is a central mediator of the cell signaling between phosphoinositide 3-kinase (PI3K) and various intracellular serine/threonine kinases including Akt/protein kinase B (PKB), p70 S6 kinases, and protein kinase C. Recent studies with cell transfection experiments have implied that PDK-1 may be involved in various cell functions including cell growth and apoptosis. However, despite its pivotal role in cellular signalings, the in vivo functions of PDK-1 in a multicellular system have rarely been investigated. Here, we have isolated Drosophila PDK-1 (dPDK-1) mutants and characterized the in vivo roles of the kinase. Drosophila deficient in the dPDK-1 gene exhibited lethality and an apoptotic phenotype in the embryonic stage. Conversely, overexpression of dPDK-1 increased cell and organ size in a Drosophila PI3K-dependent manner. dPDK-1 not only could activate Drosophila Akt/PKB (Dakt1), but also substitute the in vivo functions of its mammalian ortholog to activate Akt/PKB. This functional interaction between dPDK-1 and Dakt1 was further confirmed through genetic analyses in Drosophila. On the other hand, cAMP-dependent protein kinase, which has been proposed as a possible target of dPDK-1, did not interact with dPDK-1. In conclusion, our findings provide direct evidence that dPDK-1 regulates cell growth and apoptosis during Drosophila development via the PI3K-dependent signaling pathway and demonstrate our Drosophila system to be a powerful tool for elucidating the in vivo functions and targets of PDK-1.

Activation of the IGF-II gene by HBV-X protein requires PKC and p44/p42 map kinase signalings

We have recently shown that HBx protein, one of the causative agents of hepatocellular carcinomas, regulates Sp1 mediated transcription of insulin-like growth factor II promoter 4 (Lee et al. (1998) Oncogene 16, 2367-2380). Here we show that PKC and p44/p42MAPK signalings are required for the HBx-induced Sp1-mediated IGF-II P4 transcriptional activity since (i) PKC activation by PMA or PKC expression vector increases Sp1 phosphorylation and P4 activity in HBx-transfected HepG2 cells; (ii) PKC inhibition by PKC inhibitor Gö6976 reduces Sp1 phosphorylation, P4 activity, and IGF-II mRNA in HBx-transfected HepG2 cells; and (iii) the inhibition of MEK activation by U0126 reduces Sp1 phosphorylation, P4 activity and IGF-II mRNA in HBx-transfected HepG2 cells. These results demonstrate that PKC and p44/p42 MAPK cascades are the essential signaling pathways in Sp1-mediated IGF-II gene activation by HBx.

Protective role of superoxide dismutases against ionizing radiation in yeast

The protective role of superoxide dismutases (SODs) against ionizing radiation, which generates reactive oxygen species (ROS) harmful to cellular function, was investigated in the wild-type and in mutant yeast strains lacking cytosolic CuZnSOD (sod1Delta), mitochondrial MnSOD (sod2Delta), or both SODs (sod1Deltasod2Delta). Upon exposure to ionizing radiation, there was a distinct difference between these strains in regard to viability and the level of protein carbonyl content, which is the indicative marker of oxidative damage to protein, intracellular H2O2 level, as well as lipid peroxidation. When the oxidation of 2',7'-dichlorofluorescin was used to examine the hydroperoxide production in yeast cells, the SOD mutants showed a higher degree of increase in fluorescence upon exposure to ionizing radiation as compared to wild-type cells. These results indicated that mutants deleted for SOD genes were more sensitive to ionizing radiation than isogenic wild-type cells. Induction and inactivation of other antioxidant enzymes, such as catalase, glucose 6-phosphate dehydrogenase, and glutathione reductase, were observed after their exposure to ionizing radiation both in wild-type and in mutant cells. However, wild-type cells maintained significantly higher activities of antioxidant enzymes than did mutant cells. These results suggest that both CuZnSOD and MnSOD may play a central role in protecting cells against ionizing radiation through the removal of ROS, as well as in the protection of antioxidant enzymes.