Phospholipase Cgamma1 inhibitory principles from the sarcotestas of Ginkgo biloba

Ten phenolic compounds were isolated from the CHCl3 extract of Ginkgo biloba sarcotestas (Ginkgoaceae) as a new class of phosphatidylinositol-specific phospholipase Cgamma1 (PI-PLCgamma1) inhibitors. The substances without the long chain were ineffective. On the other hand, the activities of these compounds were dramatically decreased by acetylation of aromatic hydroxyl groups of cardanol, phenolic acid, and bilobol and by methylation of the aromatic carboxyl group of phenolic acid. The unsaturated long chain as well as the aromatic hydroxyl and carboxyl groups might play a key role for the PI-PLCgamma1 inhibitory activity. These compounds also inhibited the growth of a number of human cancer cell lines, but were less cytotoxic against a human normal colon cell line.

Auto-ADP-ribosylation of NAD glycohydrolase from Neurospora crassa

NAD glycohydrolase (NADase; EC 3.2.2.5) is an enzyme that catalyzes hydrolysis of NAD to produce ADP-ribose and nicotinamide. We recently demonstrated that self-inactivation of NADase from rabbit erythrocytes was due to an auto-ADP-ribosylation. In the present study, a mechanism of self-inactivation of NADase from Neurospora crassa by its substrate was investigated by using intact mycelia of N. crassa and purified NADase, which had molecular characteristics different from mammalian NADases. The results suggested that inactivation of NADase from N. crassa was also due to an auto-ADP-ribosylation. These findings indicate that the auto-modification of NADase is one of the universal phenomena to regulate enzyme functions.

Absence of H(+)-ATPase in the intercalated cells of renal tissues in classic distal renal tubular acidosis

Proton-secretory defect is thought to be a major pathophysiologic mechanism leading to classic distal renal tubular acidosis (dRTA). However, there have been only two case reports demonstrating the absence of proton pump in renal tissues of the patients with Sjögren's syndrome. This study presents two cases of classic dRTA in which the absence of intact H(+)-ATPase was shown in their renal biopsy tissues by immunohistochemistry using a rabbit polyclonal antibody against the 70 kDa catalytic subunit of H(+)-ATPase from bovine brain clathrin-coated vesicles; one of the cases is diagnosed as subclinical Sjögren's syndrome and the other is idiopathic dRTA. A normal human kidney (NC) and the renal biopsy tissues from a patient with chronic tubulointerstitial nephritus whose proton secretory capacity was intact (DC) were compared as controls. The first patient, a 26-year-old woman, presented with quadriparesis. Her serologic tests revealed positive autoantibodies (ANA, SSA; SSB & RF), and a lower lip biopsy confirmed the diagnosis of Sjögren's syndrome. The second patient, a 43-year-old woman, who initially presented with a pathologic fracture of both femoral necks was referred for an evaluation for hypokalemia by the Department of Orthopedic Surgery. Her renal ultrasonography showed medullary calcification, and no autoantibodies were positive. Serum electrolytes and blood gas analyses of the two patients indicated severe hypokalemia and metabolic acidosis, and proton secretory defects were shown by a failure to lower the urine pH during marked acidemia induced by NH4Cl loading and an abnormally low urine-blood pCO2 difference during bicarbonate administration. While stainings with the anti-H(+)-ATPase antibody in NC and DC were strongly positive in intercalated cells in the connecting tubules and collecting ducts, the tissues from both patients with dRTA were devoid of any anti-H(+)-ATPase staining in the intercalated cells. These results support that the pathophysiologic basis of impaired H+ secretion in idiopathic classic dRTA as well as Sjögren's syndrome is the absence of intact H(+)-ATPase pumps in the intercalated cells.

Inhibitory effect of hemin on mutagenicity of the electrophilic sulfuric acid ester of 6-hydroxymethylbenzo[a]pyrene

In the present study, we examined the effects of hemin on the mutagenicity of 6-sulfooxymethylbenzo[a]pyrene (SMBP) in Salmonella typhimurium TA98 and Chinese hamster lung fibroblast (V79) cells. The compound was tested for the possible chemoprotective activity against mutagenesis induced by SMBP and its precursor, 6-hydroxymethylbenzo[a]pyrene (HMBP), activated by hepatic cytosol and PAPS in S. typhimurium TA98. Hemin not only inhibited the mutagenic activity of SMBP in V79 cells but repressed the cytotoxicity induced by this reactive ester as demonstrated by increased cell growth. The intracellular accumulation of radioactivity in V79 cells exposed to [3H]SMBP was reduced by approximately 50% when hemin (10 microM) was added to the medium. Likewise, the formation of SMBP-DNA adducts in these cells was significantly attenuated by treatment with hemin. The covalent complex formation of hemin with SMBP was confirmed by solvent extraction and reverse-phase HPLC.

Mutagenicity of 6-sulfooxymethylbenzo[a]pyrene in Salmonella typhimurium and Chinese hamster V79 cells

6-Sulfooxymethylbenzo[a]pyrene (SMBP) is an ultimate and reactive form of 6-hydroxymethybenzo[a]pyrene (HMBP), which is converted into SMBP by the mediation of sulfotransferase. SMBP and HMBP with metabolic activation were mutagenic to S. typhimurium TA98 and TA100. The number of mutation per plate in strain TA98 was proportional to the concentrations of SMBP ranging from 0.2 to 1.0 nmol/plate, whereas that in strain TA100 was decreased at concentrations above 0.6 nmol/plate. The mutation frequencies by HMBP was also increased in a dose dependent manner in both strains. Furthermore, SMBP and HMBP were highly mutagenic and cytotoxic to Chinese hamster lung fibroblast (V79) cells. A dose-dependent increase in mutation frequencies at both hypoxanthine:guanine phosphoribosyltransferase (HGPRT) and sodium/potassium-ATPase (Na/K-ATPase) loci were found in V79 cells treated with SMBP and HMBP. The cytotoxicity of SMBP was increased with the increasing concentrations up to 2.5 microM, where the survival frequency and growth rate were decreased to almost 40% and 30% of the control value, respectively. The survival frequencies of V79 cells by HMBP were also decreased in a dose dependent manner up to 180 microM as similar to those of SMBP but the effects were less remarkable. SMBP was progressively accumulated in V79 cells, reaching plateau in just 30 min. A dose dependent increase in complex formation with DNA or proteins was observed by treatment with SMBP. The mutagenicity and cytotoxicity of SMBP and HMBP may be derived from their binding capacity to DNA in V79 cells and S. typhimurium.

Effects of follicular fluid supplementation of in-vitro maturation medium on the fertilization and development of equine oocytes after in-vitro fertilization or intracytoplasmic sperm injection

The aim of this study was to compare the effect of the addition of follicular fluid (FF) collected from preovulatory follicles with that of oestrous mare serum (EMS) (acting as the control) to TCM-199 medium on the in-vitro maturation, fertilization and development of equine cumulus-enclosed oocytes. Oocytes (<30 mm in diameter) were obtained from the ovaries of slaughtered mares. After in-vitro maturation in the presence of the two supplements, their fertilization, cleavage and developmental potential were compared after conventional in-vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) using frozen-thawed spermatozoa. Follicular fluid did not increase the maturation of oocytes to metaphase II stage compared to control. After IVF, there was no difference in fertilization rates between FF-supplemented oocytes and controls (7/87, 8.4% of oocytes showing two pronuclei with FF versus 7/116, 6% with EMS; not significant). However, after ICSI, FF-supplemented oocytes showed significantly increased normal fertilization (32/85, 37.6% of two-pronuclear oocytes) and developmental potential (15/31, 48% cleavage) compared to the control oocytes (7/47, 14.9%, P < 0.01; and 2/48, 4%, P < 0.01, respectively). Overall, ICSI resulted in increased fertilization rates compared to IVF, regardless of the presence or absence of FF (39/132, 29.5% with ICSI versus 14/203, 6.9%). These results suggest that follicular fluid supplementation may improve the maturity of equine cumulus-enclosed oocytes sufficiently for the successful use of ICSI, but not sufficiently for normal sperm-egg interaction occurring during IVF.

Hepatitis C virus E2 protein purified from mammalian cells is frequently recognized by E2-specific antibodies in patient sera

The envelope protein of hepatitis C virus (HCV) is composed of two membrane-associated glycoproteins, E1 and E2. To obtain HCV E2 protein as a secretory form at a high level, we constructed a recombinant chinese hamster ovary (CHO) cell line expressing a C-terminal truncated E2 (E2t) fused to human growth hormone (hGH), CHO/hGHE2t. The hGHE2t fusion protein was purified from the culture supernatant using anti-hGH mAb affinity chromatography at approximately 80% purity. The purified hGHE2t protein appeared to be assembled into oligomers linked by intermolecular disulfide bond(s) when density gradient centrifugation and SDS-polyacrylamide gel electrophoresis were employed. When the purified fusion protein was used for testing its ability to bind to antibodies specific for HCV by enzyme-linked immunosorbent assay, the protein was recognized by antibodies in sera from 90% of HCV-positive patients. Treatment of hGHE2t protein by beta-mercaptoethanol, but not by heat and SDS, significantly reduced its reactivity to the antibodies of patient sera, suggesting that intermolecular and/or intramolecular disulfide bonds are important for its ability to recognize its specific antibody and that the E2 protein contains discontinuous antigenic epitope(s).

Effect of chaotropic salt on the secondary structure of pigskin gelatin

Pigskin gelatin was prepared and its molecular weight profile was examined by SDS-PAGE. The major molecular weights of gelatin were 214 kDa, 135 kDa, and 122 kDa. The secondary structure of a gelatin solution in the presence of chaotropic salt was studied by using circular dichroism (CD). The CD study clearly showed that the chaotropic salt increased the ordered secondary structure of the gelatin solution due to the altered water structure.

Intracytoplasmic sperm injection (ICSI) versus conventional IVF on abattoir-derived and in vitro-matured equine oocytes

Conventional IVF as well as several assisted microfertilization techniques have shown limited success in the horse. After recent positive results achieved with intracytoplasmic injection of a single spermatozoon (ICSI) in human IVF, we chose to try the method in the horse. We compared conventional IVF to ICSI by fertilization rates of oocytes with compact and expanded cumuli and by developmental potential of the resulting embryos. Cumulus-oocyte complexes (COCs) were obtained by aspirating the follicular fluid from the ovaries of slaughtered mares. Complexes showing complete cumulus investment, either compact or expanded, were randomly assigned to IVF or ICSI trials and separately cultured for IVM. Frozen-thawed stallion spermatozoa were prepared for IVF with a swim-up procedure conducted in Talp-Hepes with heparin or for ICSI in Earle's balanced salt solution (EBSS) supplemented with human serum albumin (HSA). Oocytes for IVF were partially decumulated by pipetting, whereas those for ICSI were totally denuded with 80 UI/ml hyaluronidase. Oocytes were fixed, stained and examined for signs of fertilization the day after IVF or ICSI. The percentage of normally fertilized oocytes showing 2 pronuclei or cleavage was significantly higher with ICSI than IVF (29.8%, 17/57 vs 8.7%, 9/103 ; P < 0.01). Significantly higher fertilization rates were observed in oocytes retrieved with an expanded cumulus when submitted to ICSI procedure as compared with IVF (52.2%, 12/23 vs 17.1%, 6 35 ; P < 0.01), whereas in oocytes recovered with a compact cumulus, fertilization rates were low (14.7%, 5/34 with ICSI and 4.4%, 3 68 with IVF; NS). Embryonal development did not occur after culture following IVF, as indicated by absence of cleavage in any of the 93 inseminated oocytes. Following ICSI, 7 of 55 injected oocytes cleaved, 5 of which had shown expanded cumuli; of the 5, 2 were at the 16-cell stage and one each at the 8-, 3- and 2-cell stage, respectively. The other 2 fertilized oocytes, originating from compact cumuli, reached 4- and 8- cell stages, respectively. These results indicate that ICSI can be applied successfully to in-vitro matured equine oocytes to increase the fertilization rates. In addition, it seems that in vitro cytoplasmic maturation of oocytes issuing from a compact cumulus may not be complete enough to lead to a successful fertilization and that ICSI may be a tool to evaluate ooplasmic maturation.

Role of Rho GTPase in the endothelin-1-induced nuclear signaling

Binding of Endothelin-1 (ET-1) to its heterotrimeric G protein-coupled receptors stimulates various signaling cascades involving the activation of phospholipase C-beta, phospholipase D, protein kinase C (PKC), tyrosine kinases, Ca2+/calmodulin-dependent kinase (CaMKs), and Ras, a small molecular weight G-protein, but, the role of Rho GTPase remains unclear. In this project, we examined whether RhoA contributes to the ET-1-induced signaling cascade to c-fos SRE activation in Rat-2 fibroblast cells. Our results demonstrate that Rho activation is critical for the signal transduction of ET-1 to c-fos SRE.

The role of thiols in protecting against simultaneous toxicity of menadione to platelet plasma and intracellular membranes

Our previous study suggested that menadione (MEN) is cytotoxic to platelets of rats due to oxidative stress. To elucidate the mechanism of this toxicity, MEN-induced depletion of total cellular thiols or depletion of gutathione was studied in intact rat platelets. Treatment with MEN resulted in dose and time dependent damage to plasma (assessed by lactate dehydrogenase leakage) and intracellular (assessed by serotonin release) membranes. These events were well correlated with total cellular thiol depletion by MEN treatment, however MEN-induced glutathione depletion occurred rapidly and before plasma and intracellular membrane damage. Unlike hepatocytes, oxidized glutathione was not formed, suggesting that protein arylation, rather than oxidative stress, might be the ultimate mechanism for MEN cytotoxicity in platelets. Platelets were pretreated with dithiothreitol to supplement the total cellular thiol pool or with 1-chloro-2,4-dinitrobenzene to deplete glutathione, a soluble thiol. Dithiothreitol pretreatment to platelets protected against MEN-induced toxicity to both plasma membranes (prevented lactate dehydrogenase leakage and changes in platelet turbidity) and intracellular membranes (prevented serotonin release), although 1-chloro-2,4-dinitrobenzene pretreatment potentiated these toxicities. These results indicate that the total cellular pool of thiols plays a vital role in maintaining plasma and intracellular membrane integrity.

Chemopreventive effect of chlorophyllin on mutagenicity and cytotoxicity of 6-sulfooxymethylbenzo[a]pyrene

The chemopreventive activity of chlorophyllin (CHL) was monitored by using 6-sulfooxymethylbenzo[a]pyrene (SMBP) which is an ultimate metabolite of benzo[a]pyrene (B[a]P). CHL was quite effective in reducing both cytotoxicity and mutagenicity for SMBP in dose dependent manner up to 12.5 mM CHL in Chinese hamster V79 cells. The inhibitory patterns of CHL for SMBP were also confirmed in Salmonella typhimurium strains TA98 and TA100. Mutation frequency caused by SMBP was diminished almost to a control level at a 50 nmol CHL. A similar but less effective prevention of CHL was indicated in the mammalian and the bacterial mutagenicity assays with 6-hydroxymethylbenzo[a]pyrene (HMBP). The inhibitory effect of CHL against assault of SMBP on V79 cells was found to be related to the reduced cellular uptake of SMBP and further the remarkably lowered DNA adducts.

Regulation of NAD+ glycohydrolase activity by NAD(+)-dependent auto-ADP-ribosylation

NAD+ glycohydrolase (NADase; EC 3.2.2.5) is an enzyme that catalyses hydrolysis of NAD+ to produce ADP-ribose and nicotinamide. Its physiological role and the regulation of its enzymic activity have not been fully elucidated. In the present study, the mechanism of self-inactivation of NADase by its substrate, NAD+, was investigated by using intact rabbit erythrocytes and purified NADase. Our results suggest that inactivation of NADase was due an auto-ADP-ribosylation reaction. ADP-ribosylated NADase of rabbit erythrocytes was deADP-ribosylated when incubated without NAD+, and thus enzyme activity was simultaneously restored. These findings suggest that reversible auto-ADP-ribosylation of NADase might regulate the enzyme's activity in vivo.

Recovery of nasal physiology after functional endoscopic sinus surgery: olfaction and mucociliary transport

We assessed the changes in olfaction and mucociliary transport after functional endoscopic sinus surgery (FESS) in 80 patients with chronic paranasal sinusitis. Olfaction was evaluated with the butanol threshold test and mucociliary transport was assessed by saccharin transit time (STT). Postoperative butanol threshold scores were significantly reduced (p < 0.01), and the changes were more profound in severer forms of paranasal sinusitis as graded by ostiomeatal-unit computed tomography. The mean preoperative STT (27 min) which was significantly longer than that of controls (12 min) was significantly reduced 1, 6 and 12 months following FESS (p < 0.01). The results suggest that impairment of olfaction and mucociliary transport in chronic paranasal sinusitis may be significantly improved following FESS.

Impact of childhood cancer on Korean families

A health care system that includes institutions such as the home, clinic, or hospital as well as interpersonal relationships between providers and receivers of health care is a part of any culture. Clinical issues are a part of all cultures, and cross-cultural comparisons are useful in understanding health care. With immigration and travel, a better understanding of the situation of families who have a child with cancer in various countries, different health care systems, and different cultures is needed. Understanding the situation for families with a child who has cancer in South Korea will lead one to a better understanding of a Korean family who has immigrated to the west and has a child develop cancer or is in need of treatment.

Selectivity of phospholipase C isozymes in growth factor signaling

Xenopus laevis oocytes were injected with mRNA extracted from growth factor-responsive CCL39, Chinese hamster lung fibroblasts. The expression of functional growth factor receptors on the oocytes was demonstrated by growth factor-induced 45Ca2+ efflux. To determine the isozyme(s) of phospholipase C (PLC) coupled to growth factor receptors, growth factor-induced 45Ca2+ efflux were measured following coinjection of mRNA from CCL39 cells with PLC antibodies. PLC-gamma 1 antibody did not lead to loss of 45Ca2+ efflux induced by thrombin but resulted in loss of that induced by platelet-derived growth factor (PDGF). In contrast, PLC-delta 1 antibody did not block PDGF-induced 45Ca2+ efflux but led to inhibition of thrombin-induced 45Ca2+ efflux. PLC-beta 1 antibody did not affect Ca2+ efflux by the treatment of either thrombin or PDGF. These results suggest that these growth factor receptors are coupled to specific effectors, i.e. thrombin receptor to PLC-delta 1 and PDGF receptor to PLC-gamma 1.

Failed oocyte retrieval in in-vitro fertilization with documented positive serum beta-human chorionic gonadotrophin (HCG) concentration on day HCG+1

No oocytes were obtained at ovum retrieval in a 33-year-old patient with secondary tubal infertility, whereas in a previous cycle nine oocytes were obtained under the same ovarian stimulation protocol as used in the studied cycle. Oocyte retrieval failed in spite of the correct administration of human chorionic gonadotrophin (HCG) as demonstrated by serum beta-HCG concentration (58.6 mIU/ml) on day HCG+1. However, it was shown that progesterone failed to rise even after the administration of exogenous HCG as the luteinizing hormone signal. Therefore, when ovum retrieval fails, the serum progesterone as well as beta-HCG concentrations may be useful to help identify the cause of this unusual event.

Arterial thrombosis associated with nephrotic syndrome--a case report and review (adult cases in the English literature)

The thromboembolic complications of nephrotic syndrome are reasonably common, including spontaneous peripheral venous and/or arterial, pulmonary arterial, and renal venous occlusions. However, in comparison to the relatively high incidence of the venous thromboembolic complications with hypercoagulable status, arterial thromboses have been reported much less and it was only 20 cases in the English literature so far. Furthermore, the most cases were pediatric patients rather than adults. Therefore, this report describes an adult nephrotic cases complicated by superior mesenteric artery thrombosis leading to death via catastrophic hospital course. Also, we reviewed the literature in English regarding cases of arterial thromboses in adult nephrotic patients with special interest to locations of thrombosis, underlying histopathologic types of glomerulopathy, and use of steroids or diuretics before its development.

Multistep photorefractive keratectomy for high myopia

Nineteen human myopic eyes exceeding -8.00 D underwent multi-step excimer laser photorefractive keratectomy (PRK) with 6-month follow up. We performed two or three step PRK at the same time according to the amount of myopia present. The preoperative refraction ranged from -8.87 D to -16.99 D (mean -12.28 D). The mean attempted correction was 7.83 D. Six months after surgery, the mean refraction was -2.23 D. Keratometry demonstrated stable flattening of the cornea, and pachometry showed central cornea thinning. Seventeen eyes had clear or trace corneal haze. Above results showed multi-step PRK is a safe and relatively efficient procedure for correction of high myopia, but long-term follow up will be necessary to determine the stability of this procedure.