Colonoscopic findings in intestinal Behçet's disease

The aims of this study were to investigate the clinical and colonoscopic characteristics of patients with intestinal Behçet's disease and to compare the findings of typical and atypical intestinal Behçet's disease. Ninety-four patients diagnosed as having intestinal Behçet's disease were included. Of these, we considered 42 patients as having complete or incomplete type; these fulfilled the international criteria as "typical," and the other 52 patients were classified as having "atypical" intestinal Behçet's disease. Abdominal pain was the most common symptom (92%), followed by diarrhea and gastrointestinal bleeding. All of the 22 patients with a history of surgery had ulcers at the anastomotic site. Most of the patients, who had never been operated on, had lesions in the ileocecal area (96%). Sixty-three patients (67%) had a single ulcer. Many (76%) of the ulcers were larger than 1 cm, and the mean size of the ulcers was 2.9 cm. Most (99%) of the ulcers were round/oval or geographic in shape. Usually ulcers were deep (62%), and their margins discrete (80%). There was no difference in the endoscopic findings of typical and atypical intestinal Behçet's disease. Typical colonoscopic findings in intestinal Behçet's disease were single or a few deep ulcers with discrete margins in the ileocecal area or anastomotic site. Endoscopic characteristics of patients with intestinal involvement in the case of "suspect" or "possible" type of Behçet's disease that lack the systemic manifestations of Behçet's disease were in accord with those in "complete" or "incomplete" types of Behçet's disease, who fulfill the International Study Group for Behçet's Disease criteria.

Lymphosarcoma in a brown bear (Ursus arctos)

An example of lymphoblastic lymphosarcoma was found in a 7-year-old male brown bear (Ursus arctos) that died after having a 7-month history of depression, anorexia and watery diarrhea. Grossly the mesenteric lymph nodes were enlarged to approximately 4 to 6 times their normal size and histologically diagnosed as lymphoblastic lymphosarcoma. The small intestinal mucosa was corrugated and had severe mural thickening due to infiltrated neoplastic cells. Hepatic metastasis was also noted. This is the first reported case of lymphosarcoma in Ursidae in Korea. As an incidental finding, endogenous lipid pneumonia was noted in the lung.

Anterior and posterior medialization (APM) thyroplasty

OBJECTIVE

In unilateral vocal fold paralysis with dysphonia, most of the paralyzed vocal folds may be medialized effectively by medialization laryngoplasty. However, if the posterior glottal gap is wide, these procedures may sometimes have a limit to medialize the posterior glottis and cannot be effective for acceptable voice quality. The objective of this study is to introduce a new surgical technique for medializing the membranous and cartilaginous portions of the paralyzed vocal fold: anterior and posterior medialization (APM) thyroplasty.

METHOD

Six patients underwent APM thyroplasty. They completed preoperative and postoperative evaluation with acoustic analysis and video laryngoscopy.

RESULTS

All patients satisfied their voice subjectively after surgery. The paralyzed vocal folds, membranous and cartilaginous parts, were medialized well, and the paralyzed arytenoid showed less anterior tipping postoperatively. On voice analysis all patients showed prolonged phonation times and decreased perturbations after surgery.

CONCLUSION

The advantages of this procedure are to medialize the membranous and cartilaginous portions of the paralyzed vocal fold directly and to correct vertical mismatch between two vocal folds. This procedure might be especially indicated in the lateralized position of the paralyzed vocal fold but not in the higher paralyzed vocal fold compared with the normal vocal fold.

Cervical dermal sinus associated with dermoid cyst

We report a rare case of cervical dermal sinus associated with a dermoid cyst in a 10-month-old infant, who presented with a 1-month history of motor weakness of the right upper extremity. Magnetic resonance imaging showed an intradural extramedullary dermoid cyst extending from C3 to C4, which was connected with the skin dimple along the sinus tract. Total excision of the dermoid cyst and the sinus tract with C3-5 laminectomy resulted in good functional recovery.

Expression of pregnancy-associated glycoprotein 1 and 2 genes in in vivo, in vitro and parthenogenetically derived preimplantation pig embryos

The objective of this study was to determine whether porcine PAG (poPAG) genes are expressed in embryos as they develop from the 1-cell stage to expanded blastocysts, and whether expression differed according to how embryos had been derived. Embryos at various preimplantation stages were assayed after in vivo fertilisation, after in vitro fertilisation of in vitro-matured oocytes, or following parthenogenetic activation of in vitro-matured oocytes. The presence of PAG transcripts was determined at the 1-, 2-, and 4-cell, compact morula and blastocyst stages by reverse transcription-PCR procedures with PAG 1- and PAG 2-specific primers, followed by Southern blotting. The mRNAs for poPAG 1 and 2 were detected in in vitro-derived, in vivo-derived and parthenogenetically derived blastocyst stage embryos. In some replications poPAG 1 could be detected as early as the compact morula stage and poPAG 2 could be detected as early as the 4-cell stage. Our study revealed that poPAG 1 and 2 genes are expressed as early as the compact morula stage and 4-cell stage, respectively, in normal embryos and in parthenogenetically derived blastocysts. Thus it appears that the poPAGs are not maternally imprinted and they may be useful as potential candidates for markers of developmental competence.

Secondary amenorrhea caused by hydrocephalus due to aqueductal stenosis : report of two cases

Amenorrhea is rarely presented as a manifestation of endocrinological disturbances in patients of chronic hydrocephalus. We describe two cases of secondary amenorrhea caused by hydrocephalus due to aqueductal stenosis. Two female patients of age 30 and 20 yr presented with amenorrhea and increasing headache. Magnetic resonance images revealed marked, noncommunicating hydrocephalus without any tumorous lesion. In one patient, emergent extraventricular drainage was necessary because of progressive neurological deterioration. Each patient underwent surgical intervention for the hydrocephalus-ventriculoperitoneal shunt and endoscopic third ventriculostomy. Both resumed normal menstruation continuing so far with further normal menstrual bleeding. These two cases and others reported in the literature indicated that the surgical intervention for hydrocephalus resolves amenorrhea in all the cases of amenorrhea due to hydrocephalus. The suspected role of the surgery is the correction of increased intracranial pressure, which is an important pathogenetic factor in the development of amenorrhea.

Observation of an anomalous number of dimuon events in a high energy neutrino beam

A search for long-lived neutral particles ( N0's) with masses above 2.2 GeV/c(2) that decay into at least one muon has been performed using an instrumented decay channel at the NuTeV experiment at Fermilab. Data were examined for particles decaying into the final states mumu, mu(e), and mu(pi). Three mumu events were observed over an expected standard model background of 0.069+/-0.010 events; no events were observed in the other modes.

Implication of the small GTPase Rac1 in the apoptosis induced by UV in Rat-2 fibroblasts

Exposure of mammalian cells to ultraviolet (UV) light elicits a cellular response and also lead to apoptotic cell death. However, the role of Rac, a member of Rho family GTPases, in the UV-induced apoptosis has never been examined. In UV-irradiated Rat-2 fibroblasts, nuclear fragmentation began to be observed within 2 h and the total viability of Rat-2 cells were only about 15% at 6 h following by UV irradiation, whereas the total viability in Rat2-Rac(N17) cells stably expressing RacN17, a dominant negative Rac1 mutant, was almost close to 67%. Pretreatment with SB203580, a specific inhibitor of p38 kinase, likewise attenuated UV-induced cell death, but PD98059, a MEK inhibitor, did not. Thus, Rac1 and p38 kinase appear to be components in the apoptotic signaling pathway induced by UV irradiation in Rat-2 fibroblasts. In addition, our results show that p38 kinase stimulation by UV is dramatically inhibited by RacN17, suggesting that p38 kinase is situated downstream of Rac1 in the UV signaling to apoptosis.

Mutational and kinetic evaluation of conserved His-123 in dual specificity protein-tyrosine phosphatase vaccinia H1-related phosphatase: participation of Tyr-78 and Thr-73 residues in tuning the orientation of His-123

Active-site cysteine strategically positioned in the P-loop of protein-tyrosine phosphatases has been suggested to be further stabilized by hydrogen bonding arrays radiating out from the P-loop to neighboring residues. In this work, we investigated the structural role of histidine array in HC(X)(5)RS motif of the vaccinia H1-related protein phosphatase (VHR), using site-directed mutagenesis in conjunction with an extensive kinetic analysis. Conserved His-123 was mutated along with neighboring residues Tyr-78 and Thr-73. The increased pK(a) values of active-site Cys-124 found in Y78F and T73A mutants (6.51 and 6.75, respectively) were comparable to those of H123A and H123F mutants. Kinetic evaluation of Y78F and T73A mutants further implicates that the mutations perturb the relative position of Cys-124 within the P-loop. These results imply that Tyr-78 and Thr-73 make up an essential part of the His-123 array and structurally tune the Cys-124 position. Tyr-78 of VHR turns out to be the invariant Tyr reported in several protein-tyrosine phosphatases by a structure-based sequence alignment. Therefore, orientation of the imidazole ring of His-123 by the invariant Tyr-78 is crucial for maintaining the proper position of Cys-124 in the P-loop.

Selective increases in HIV-specific neutralizing antibody and partial reconstitution of cellular immune responses during prolonged, successful drug therapy of HIV infection

Because the immune response to HIV depends on viral gene expression, we examined the HIV-specific immune responses in persons whose viral load after highly active antiretroviral therapy (HAART) was <400 on at least 3 occasions over a 12-month interval. Eleven patients were identified. While there was little change in mean HIV-binding antibody (Ab) titers in this group, two persons mounted increases in HIV envelope-specific binding antibody. Neutralizing antibody (NAb) titers against a panel of HIV-1 primary isolates (BZ167, US1, and CM237) increased post-HAART (80% neutralization titer against US1, p = 0.06; against CM237, p = 0.04). The two persons with large increases in binding antibody also had increases in primary isolate NAb. Roughly half of HAART recipients had significant increases in neutralizing antibody to the primary isolates US1 and CM237. Compared with CD4-matched, non-HAART controls, there were significant increases in NAb against the subtype B primary isolate US1 (p < 0.0009); no increases were seen against more easily neutralized primary isolate BZ167. There were no differences after HAART in antibody-directed cellular cytotoxicity (ADCC). HAART resulted in a partial restoration of lymphoproliferative responses to recall antigens (tetanus and diphtheria). New responses developed to HIV Gag p24. No patient responded to HIV Env gp160 or gp120 either before or after HAART. The data underscore the lack of functional reconstitution of HIV-specific, CD4-mediated responses despite durable suppression of viral replication. In the setting of stable anti-HIV Ab levels, the development of increased NAb in certain individuals suggests that control of the virus by HAART may assist in immune control of HIV.

Rac and p38 kinase mediate 5-lipoxygenase translocation and cell death

5-Lipoxygenase (5-LO) is a key enzyme involved in the synthesis of leukotrienes from arachidonic acid, and its activation is usually followed by translocation to the nuclear envelope. The details of mechanisms involved in the translocation of 5-LO are not well understood, though Ca(2+) is known to be essential. Here we show that ionomycin, a Ca(2+) ionophore, induces 5-LO translocation and necrotic cell death in Rat-2 fibroblasts, suggesting a potential relationship between activation of 5-LO and cell death. These effects were markedly attenuated in Rat2-Rac(N17) cells expressing a dominant negative Rac1 mutant. Pretreatment with SB203580, a specific inhibitor of p38 MAP kinase, or EGTA, a Ca(2+) chelator, likewise diminished ionomycin-induced 5-LO translocation and cell death, but PD98059, a MEK inhibitor, did not. Thus, Rac and p38 MAP kinase appear to be components in a Ca(2+)-dependent pathway leading to 5-LO translocation and necrotic cell death in Rat-2 fibroblasts.

Acute urinary toxicity following transperineal prostate brachytherapy using a modified Quimby loading method

PURPOSE

To examine the acute urinary toxicity following transperineal prostate implant using a modified Quimby loading method with regard to time course, severity, and factors that may be associated with a higher incidence of morbidity.

METHODS AND MATERIALS

One hundred thirty-nine patients with prostate adenocarcinoma treated with brachytherapy from 1997 through 1999 had follow-up records available for review. Patients considered for definitive brachytherapy alone included those with prostate specific antigen (PSA) < or = 6, Gleason score (GS) < or = 6, clinical stage < T2b, and prostate volumes generally less than 40 cc. Patients with larger prostate volumes were given neoadjuvant antiandrogen therapy. Those with GS > 6, PSA > 6, or Stage > T2a were treated with external beam radiation therapy followed by brachytherapy boost. Sources were loaded according to a modified Quimby method. At each follow-up, toxicity was graded based on a modified RTOG urinary toxicity scale.

RESULTS

Acute urinary toxicity occurred in 88%. Grade I toxicity was reported in 23%, grade II in 45%, and grade III in 20%, with 14% requiring prolonged (greater than 1 week) intermittent or indwelling catheterization. Overall median duration of symptoms was 12 months. There was no difference in duration of symptoms between patients treated with I-125 or Pd-103 sources (p = 0.71). After adjusting for GS and PSA, multivariate logistic regression analysis showed higher incidence of grade 3 toxicity in patients with larger prostate volumes (p = 0.002), and those with more seeds implanted (p < 0.001). Higher incidence of prolonged catheterization was found in patients receiving brachytherapy alone (p = 0.01), with larger prostate volumes (p = 0.01), and those with more seeds implanted (p < 0.001).

CONCLUSION

Interstitial brachytherapy for prostate cancer leads to a high incidence of acute urinary toxicity, most of which is mild to moderate in severity. A prolonged need for catheterization can occur in some patients. Patients receiving brachytherapy alone, those with prostate volumes greater than 30 cc, and those implanted with a greater number of seeds have the highest incidence of significant toxicity.

Tripartite structure of Saccharomyces cerevisiae Dna2 helicase/endonuclease

In order to gain insights into the structural basis of the multifunctional Dna2 enzyme involved in Okazaki fragment processing, we performed biochemical, biophysical and genetic studies to dissect the domain structure of Dna2. Proteolytic digestion of Dna2 using subtilisin produced a 127 kDa polypeptide that lacked the 45 kDa N-terminal region of Dna2. Further digestion generated two subtilisin-resistant core fragments of approximately equal size, 58 and 60 kDa. Surprisingly, digestion resulted in a significant (3- to 8-fold) increase in both ATPase and endonuclease activities compared to the intact enzyme. However, cells with a mutant DNA2 allele lacking the corresponding N-terminal region were severely impaired in growth, being unable to grow at 37 degrees C, indicating that the N-terminal region contains a domain critical for a cellular function(s) of Dna2. Analyses of the hydrodynamic properties of and in vivo complex formation by wild-type and/or mutant Dna2 lacking the N-terminal 45 kDa domain revealed that Dna2 is active as the monomer and thus the defect in the mutant Dna2 protein is not due to its inability to multimerize. In addition, we found that the N-terminal 45 kDa domain interacts physically with a central region located between the two catalytic domains. Our results suggest that the N-terminal 45 kDa domain of Dna2 plays a critical role in regulation of the enzymatic activities of Dna2 by serving as a site for intra- and intermolecular interactions essential for optimal function of Dna2 in Okazaki fragment processing. The possible mode of regulation of Dna2 is discussed based upon our recent finding that replication protein A interacts functionally and physically with Dna2 during Okazaki fragment processing.

Ethanol decreases the expression of mitochondrial cytochrome c oxidase mRNA in the rat

To evaluate the molecular and cellular bases of effects of ethanol on the brain, we utilized a differential display-polymerase chain reaction. Several cDNA fragments were differentially expressed in the hippocampus of control vs. ethanol-treated rats. One of these genes was homologous to the rat mitochondrial cytochrome c oxidase mRNA. Northern blot analysis revealed that the expression of this message in the whole hippocampus was clearly lower after ethanol treatment. Using in situ hybridization, we also found that cytochrome c oxidase mRNA expression, especially in the CA1 and CA3 of the hippocampal regions, was significantly decreased by ethanol treatment. As cytochrome c oxidase is related to oxidative stress, the present study suggests that ethanol might affect the brain through modulation of an oxidative stress reaction.

Role of the cytosolic phospholipase A2-linked cascade in signaling by an oncogenic, constitutively active Ha-Ras isoform

Activation of Ras signaling by growth factors has been associated with gene regulation and cell proliferation. Here we characterize the contributory role of cytosolic phospholipase A(2) in the oncogenic Ha-Ras(V12) signaling pathway leading to activation of c-fos serum response element (SRE) and transformation in Rat-2 fibroblasts. Using a c-fos SRE-luciferase reporter gene, we showed that the transactivation of SRE by Ha-Ras(V12) is mainly via a Rac-linked cascade, although the Raf-mitogen-activated protein kinase cascade is required for full activation. In addition, Ha-Ras(V12)-induced DNA synthesis was significantly attenuated by microinjection of recombinant Rac(N17), a dominant negative mutant of Rac1. To identify the mediators downstream of Rac in the Ha-Ras(V12) signaling, we investigated the involvement of cytosolic phospholipase A(2). Oncogenic Ha-Ras(V12)-induced SRE activation was significantly inhibited by either pretreatment with mepacrine, a phospholipase A(2) inhibitor, or cotransfection with the antisense oligonucleotide of cytosolic phospholipase A(2). We also found cytosolic phospholipase A(2) to be situated downstream of Ha-Ras(V12) in a signal pathway leading to transformation. Together, these results are indicative of mediatory roles of Rac and cytosolic phospholipase A(2) in the signaling pathway by which Ha-Ras(V12) transactivates c-fos SRE and transformation. Our findings point to cytosolic phospholipase A(2) as a novel potential target for suppressing oncogenic Ha-Ras(V12) signaling in the cell.

Acyl-CoA synthetase isoforms 1, 4, and 5 are present in different subcellular membranes in rat liver and can be inhibited independently

Inhibition studies have suggested that acyl-CoA synthetase (ACS, EC ) isoforms might regulate the use of acyl-CoAs by different metabolic pathways. In order to determine whether the subcellular locations differed for each of the three ACSs present in liver and whether these isoforms were regulated independently, non-cross-reacting peptide antibodies were raised against ACS1, ACS4, and ACS5. ACS1 was identified in endoplasmic reticulum, mitochondria-associated membrane (MAM), and cytosol, but not in mitochondria. ACS4 was present primarily in MAM, and the 76-kDa ACS5 protein was located in mitochondrial membrane. Consistent with these locations, N-ethylmaleimide, an inhibitor of ACS4, inhibited ACS activity 47% in MAM and 28% in endoplasmic reticulum. Troglitazone, a second ACS4 inhibitor, inhibited ACS activity <10% in microsomes and mitochondria and 45% in MAM. Triacsin C, a competitive inhibitor of both ACS1 and ACS4, inhibited ACS activity similarly in endoplasmic reticulum, MAM, and mitochondria, suggesting that a hitherto unidentified triacsin-sensitive ACS is present in mitochondria. ACS1, ACS4, and ACS5 were regulated independently by fasting and re-feeding. Fasting rats for 48 h resulted in a decrease in ACS4 protein, and an increase in ACS5. Re-feeding normal chow or a high sucrose diet for 24 h after a 48-h fast increased both ACS1 and ACS4 protein expression 1.5-2.0-fold, consistent with inhibition studies. These results suggest that ACS1 and ACS4 may be linked to triacylglycerol synthesis. Taken together, the data suggest that acyl-CoAs may be functionally channeled to specific metabolic pathways through different ACS isoforms in unique subcellular locations.

Expression and characterization of recombinant rat Acyl-CoA synthetases 1, 4, and 5. Selective inhibition by triacsin C and thiazolidinediones

Inhibition by triacsins and troglitazone of long chain fatty acid incorporation into cellular lipids suggests the existence of inhibitor-sensitive and -resistant acyl-CoA synthetases (ACS, EC ) that are linked to specific metabolic pathways. In order to test this hypothesis, we cloned and purified rat ACS1, ACS4, and ACS5, the isoforms present in liver and fat cells, expressed the isoforms as ACS-Flag fusion proteins in Escherichia coli, and purified them by Flag affinity chromatography. The Flag epitope at the C terminus did not alter the kinetic properties of the enzyme. Purified ACS1-, 4-, and 5-Flag isoforms differed in their apparent K(m) values for ATP, thermolability, pH optima, requirement for Triton X-100, and sensitivity to N-ethylmaleimide and phenylglyoxal. The ACS inhibitor triacsin C strongly inhibited ACS1 and ACS4, but not ACS5. The thiazolidinedione (TZD) insulin-sensitizing drugs and peroxisome proliferator-activated receptor gamma (PPARgamma) ligands, troglitazone, rosiglitazone, and pioglitazone, strongly and specifically inhibited only ACS4, with an IC(50) of less than 1.5 microm. Troglitazone exhibited a mixed type inhibition of ACS4. alpha-Tocopherol, whose ring structure forms the non-TZD portion of troglitazone, did not inhibit ACS4, indicating that the thiazolidine-2,4-dione moiety is the critical component for inhibition. A non-TZD PPARgamma ligand, GW1929, which is 7-fold more potent than rosiglitazone, inhibited ACS1 and ACS4 poorly with an IC(50) of greater than 50 microm, more than 100-fold higher than was required for rosiglitazone, thereby demonstrating the specificity of TZD inhibition. Further, the PPARalpha ligands, clofibrate and GW4647, and various xenobiotic carboxylic acids known to be incorporated into complex lipids had no effect on ACS1, -4, or -5. These results, together with previous data showing that triacsin C and troglitazone strongly inhibit triacylglycerol synthesis compared with other metabolic pathways, suggest that ACS1 and ACS4 catalyze the synthesis of acyl-CoAs used for triacylglycerol synthesis and that lack of inhibition of a metabolic pathway by triacsin C does not prove lack of acyl-CoA involvement. The results further suggest the possibility that the insulin-sensitizing effects of the thiazolidinedione drugs might be achieved, in part, through direct interaction with ACS4 in a PPARgamma-independent manner.

Actin Directly Interacts with Phospholipase D, Inhibiting Its Activity

Mammalian phospholipase D (PLD) plays a key role in several signal transduction pathways and is involved in many diverse functions. To elucidate the complex molecular regulation of PLD, we investigated PLD-binding proteins obtained from rat brain extract. Here we report that a 43-kDa protein in the rat brain, beta-actin, acts as a major PLD2 direct-binding protein as revealed by peptide mass fingerprinting in combination with matrix-assisted laser desorption ionization/time-of-flight mass spectrometry. We also determined that the region between amino acids 613 and 723 of PLD2 is required for the direct binding of beta-actin, using bacterially expressed glutathione S-transferase fusion proteins of PLD2 fragments. Intriguingly, purified beta-actin potently inhibited both phosphatidylinositol-4,5-bisphosphate- and oleate-dependent PLD2 activities in a concentration-dependent manner (IC50 = 5 nm). In a previous paper, we reported that alpha-actinin inhibited PLD2 activity in an interaction-dependent and an ADP-ribosylation factor 1 (ARF1)-reversible manner (Park, J. B., Kim, J. H., Kim, Y., Ha, S. H., Kim, J. H., Yoo, J.-S., Du, G., Frohman, M. A., Suh, P.-G., and Ryu, S. H. (2000) J. Biol. Chem. 275, 21295-21301). In vitro binding analyses showed that beta-actin could displace alpha-actinin binding to PLD2, demonstrating independent interaction between cytoskeletal proteins and PLD2. Furthermore, ARF1 could steer the PLD2 activity in a positive direction regardless of the inhibitory effect of beta-actin on PLD2. We also observed that beta-actin regulates PLD1 and PLD2 with similar binding and inhibitory potencies. Immunocytochemical and co-immunoprecipitation studies demonstrated the in vivo interaction between the two PLD isozymes and actin in cells. Taken together, these results suggest that the regulation of PLD by cytoskeletal proteins, beta-actin and alpha-actinin, and ARF1 may play an important role in cytoskeleton-related PLD functions.

Is it necessary to resect the diseased esophagus in performing reconstruction for corrosive esophageal stricture?

OBJECTIVE

The incidence of carcinoma of the esophagus among patients with chronic esophageal stricture caused by ingestion of corrosive agents is reported to be significantly higher than that of the general population. The question of whether or not a resection of the diseased esophagus should be included in the surgical reconstruction procedure of the undilatable esophageal stricture continues to be a controversial.

METHODS

During the 12 year period from 1988 to 1999, a total of 54 consecutive patients with caustic stricture of the esophagus were treated in our department. We retrospectively reviewed these cases and analyzed the incidence of cicatrical carcinoma among the patients and the risk of esophagectomy according to the procedures performed.

RESULTS

We found seven cases of esophageal cancer among these patients. There was no significant increase in mortality or morbidity related to esophagectomy.

CONCLUSIONS

Considering the high incidence of cicatrical carcinoma from the stricture sites as well as the possible chance of hidden malignancy, we concluded that the simultaneous resection of the esophagus with reconstruction for patients with chronic intractable caustic stricture would give the patients a better probability of being completely cured of the disease.

Emergence of YMDD motif mutant of hepatitis B virus during short-term lamivudine therapy in South Korea

BACKGROUND/AIMS

The emergence of a YMDD mutant resistant to lamivudine therapy has been reported in patients with hepatitis B treated with long-term lamivudine therapy. However, it is not well known whether the YMDD mutant could be detected early in lamivudine therapy in hepatitis B virus (HBV) endemic areas. The aim of this study was to investigate the emergence of the YMDD mutant during short-term lamivudine therapy in South Korea.

METHODS

We prospectively investigated the emergence of the YMDD mutant by the nested PCR assay using restriction fragment length polymorphism in 28 patients with chronic hepatitis B who were treated with 100 mg of lamivudine daily for 12 weeks.

RESULTS

The YMDD mutant was detected in 17 (60.7%) out of 28 patients at week 12, and the only type of mutation found was the YIDD mutation. When we carried out the nested PCR serially in five patients, YIDD mutants were detected as early as 2 weeks by the nested PCR assay. The nested PCR results were in concordance with DNA sequencing in one patient's serial samples.

CONCLUSIONS

YMDD mutants in HBV were detected within a few weeks during lamivudine therapy in South Korea, which suggests that the YMDD mutant may exist even before lamivudine therapy in HBV endemic areas.

A simple method for the purification of an antimicrobial peptide in recombinant Escherichia coli

A magainin derivative, designated MSI-344, was produced in Escherichia coli as fusion protein, by utilizing a truncated amidophsphoribosyltransferase of E. coli as a fusion partner. Bacterial cells transformed with the gene encoding the fusion protein were grown to a high cell density and induced with isopropyl-1-thio-b-D-galatoside (IPTG) to initiate product expression. The fusion protein was accumulated into cytoplasmic inclusion body and recombinant MSI-344 was released from the fusion partner by hydroxylamine treatment. Following cleavage of the fusion protein with hydroxylamine, the released MSI-344 was purified to homogeneity by cationic exchange chromatography. The final purity was at least 95% by reversed-phase high performance liquid chromatography (RP-HPLC). Purified recombinant MSI-344 was found to be indistinguishable from the synthetic peptide determined by amino acid sequences and antimicrobial activity assay.

Establishment of the prediction table of parturition day with ultrasonography in small pet dogs

To establish a prediction table of parturition day the real-time B-mode ultrasonographic examinations were performed in the 8 pregnant Malteses and 10 Yorkshire terriers (total pups, 25 and 38 pups, respectively) from 18 days of gestation until the parturition. Ovulation was designated the first day of gestation (day 0). Extra fetal and fetal structures were measured from all conceptues. The parameters that exhibited the best correlation to parturition were used to compile a prediction table of parturition day. To testify the precision of the prediction table of parturition day, the 15 pregnant Malteses (48 pups) and 13 pregnant Yorkshire terriers (42 pups) with unknown mating time were examined using ultrasonography. Inner chorionic cavity diameter on days 18 to 37 and fetal head diameter on day 38 to parturition that showed the best correlation to gestational age were the most pertinent to the estimation of gestational age and the prediction of parturition day. The two parameters were used to compile a prediction table of parturition with averaged regression equations. In verificational examinations, with the exception of I Yorkshire terrier (3.6%) having 1 fetus, 18 of 28 bitches (64.3%) delivered exactly on the date predicted and 9 of 28 bitches (32.1%) delivered within I day of the date predicted. Therefore, the prediction table of parturition day seems to be a useful tool of the prediction of parturition day in practice.

Radiologic findings of Behçet syndrome involving the gastrointestinal tract

Behçet syndrome is characterized by the histopathologic finding of nonspecific vasculitis in multiple organs. The diagnosis is usually made on the basis of the combination of clinical signs and symptoms. This disease involves the gastrointestinal tract in 10%-50% of patients, and the terminal ileum and cecum are chiefly affected. Barium study is useful in demonstrating the characteristic radiographic features of Behçet syndrome involving the gastrointestinal tract. The presence of deep, penetrating ulcers results in a high rate of complications, such as perforation, fistula, hemorrhage, and peritonitis. Furthermore, recurrence of disease adjacent to or at the surgical anastomosis is common. Computed tomography is useful in determining the extent of the lesions and in identifying cases in which complications are likely to occur. Familiarity with the various radiologic findings of Behçet syndrome involving the gastrointestinal tract helps in making an early diagnosis, as well as in establishing an appropriate treatment strategy.

Role of disinfectant concentration and pH in the inactivation kinetics of Cryptosporidium parvum oocysts with ozone and monochloramine

The objective of this study was to investigate the effect of disinfectant concentration and pH on the inactivation kinetics of Cryptosporidium parvum oocysts with ozone, monochloramine, and ozone/monochloramine at 20 degrees C. Experimental results revealed that the CT (product of disinfectant concentration and contact time) required to achieve a certain level of C. parvum inactivation was unique, thus demonstrating the validity of the CT concept for these single disinfectant and sequential disinfection processes for the range of experimental conditions investigated. Inactivation curves were represented accurately by a delayed Chick-Watson expression consistent with the CT concept. No pH dependence was observed for primary inactivation with ozone in the pH range of 6-10 or primary and secondary inactivation with monochloramine at pH values of 8 and 10. Oocyst resistance to chemical disinfectant attack was found to vary among oocysts lots as well as with oocyst aging within a given lot. The synergy observed for sequential disinfection with ozone/monochloramine suggested that monochloramine might be reacting with some of the same chemical constituents, both vital and nonvital, of the oocyst wall and/or cavity that also react with ozone. If so, partial completion of these reactions by the primary disinfectant would have resulted in the disappearance of the lag phase and the faster rate of inactivation observed for the secondary disinfectant.