Endoscopic retrograde pancreatographic findings of pancreatic lipomatosis

Pancreatic lipomatosis is characterized by fatty infiltration or replacement of the pancreas, and has been associated with many conditions. We recently experienced two cases of pancreatic lipomatosis in patients with pancreatic pseudocyst and a case of lipomatosis in diabetes mellitus. In these patients, abrupt obstruction of the main pancreatic duct with smooth tapering is a typical endoscopic retrograde pancreatography (ERP) finding of pancreatic lipomatosis and must be differentiated with pancreatic carcinoma.

The relationship between plasma leptin and nutritional status in chronic hemodialysis patients

Leptin serves an important role in suppressing appetite in mice and is known to be elevated in chronic renal failure (CRF) patients. But clinical significance of leptin as an appetite-reducing uremic toxin, remains to be determined. So we studied the relationship between plasma leptin and nutritional status in 46 chronic hemodialysis (HD) patients. Pre HD leptin was measured and divided by body mass index (BMI) to give adjusted leptin levels. KT/Vurea (K, dialyzer urea clearance; T, duration of HD; V, volume of distribution of urea), C-reactive protein (CRP), plasma insulin and nutritional parameters such as serum albumin, normalized protein catabolic rate (nPCR), subjective global assessment (SGA), BMI and mid-arm muscle circumference (MAMC) were also measured. Mean plasma leptin levels were 8.13+/-2.91 ng/mL (male 3.15+/-0.70; female 14.07+/-6.14, p<0.05). Adjusted leptin levels were positively correlated with nPCR (male r=0.47, p<0.05; female r=0.46, p<0.05), SGA (male r=0.43, p<0.05; female r=0.51, p<0.05) and MAMC (male r=0.60, p<0.005; female r=0.61, p<0.05). They did not correlate with KT/Vurea, serum albumin, hematocrit, bicarbonate, insulin and CRP. Presence of DM and erythropoietin therapy had no effect on leptin levels. These results suggest that leptin is a marker of good nutritional status rather than a cause of protein energy malnutrition in chronic HD patients.

Pathogenesis of diabetic nephropathy: the role of oxidative stress and protein kinase C

Hyperglycemia, a well recognized pathogenetic factor of long-term complications in diabetes mellitus, not only generates more reactive oxygen species but also attenuates antioxidative mechanisms through glycation of the scavenging enzymes. Therefore, oxidative stress has been considered to be a common pathogenetic factor of the diabetic complications including nephropathy. A causal relationship between oxidative stress and diabetic nephropathy has been established by observations that (1) lipid peroxides and 8-hydroxydeoxyguanosine, indices of oxidative tissue injury, were increased in the kidneys of diabetic rats with albuminuria; (2) high glucose directly increases oxidative stress in glomerular mesangial cells, a target cell of diabetic nephropathy; (3) oxidative stress induces mRNA expression of TGF-beta1 and fibronectin which are the genes implicated in diabetic glomerular injury, and (4) inhibition of oxidative stress ameliorates all the manifestations associated with diabetic nephropathy. Proposed mechanisms involved in oxidative stress associated with hyperglycemia are glucose autooxidation, the formation of advanced glycosylation end products, and metabolic stress resulting from hyperglycemia. Since the inhibition of protein kinase C (PKC) effectively blocks not only phorbol ester-induced but also high glucose- and H2O2-induced fibronectin production, the activation of PKC under diabetic conditions may also have a modulatory role in oxidative stress-induced renal injury in diabetes mellitus.

Testicular cytotoxicity of DA-125, a new anthracycline anticancer agent, in rats

To assess the testicular cytotoxicity induced by DA-125, a new anthracycline anticancer agent, 50 male Sprague Dawley rats were randomly assigned to five groups, with 10 rats in each group, and were given different single intravenous doses of DA-125 at dose levels of 0, 6.25, 12.5, 25, and 50 mg/kg body weight. On Day 56 after treatment, all male rats were killed and necropsied. Parameters of testicular cytotoxicity included genital organ weights, testicular sperm head counts, epididymal sperm motility and morphology, repopulation index, epididymal index, and histopathologic examinations. At 25 and 50 mg/kg, the weights of testes, epididymides, and seminal vesicles were reduced dose-dependently, but prostate weight was not different among the groups. At 50 mg/kg, the number of testicular sperm heads was decreased. However, the motility and morphology of epididymal sperm were comparable to the control values. On histopathologic examination, atrophy of seminiferous tubules, loss or decrease of germ cells, formation of multinucleated giant cells, and/or vacuolization of Sertoli cells in the testis were observed at 25 and 50 mg/kg. In addition, decreased sperm content and increased degenerative germ cells in the ductus epididymis were also found. Some recovery of spermatogenesis was observed at 25 mg/kg, whereas a decline in the repopulation index was observed at 50 mg/kg, indicating that the surviving stem cells had become unable to produce differentiated germ cells to enter the spermatogenic pathway. There was no evidences of testicular cytotoxicity at 6.25 and 12.5 mg/kg. These results indicate that administration of a single dose of DA-12.5 (25 to 50 mg/kg) results in testicular damage in male Sprague-Dawley rats.

Response to chloroquine of Plasmodium vivax among South Korean soldiers

The response to standard chloroquine treatment was evaluated, by microscopical examination of blood-smears, among 81 soldiers diagnosed with Plasmodium vivax malaria in South Korea in 1996. The smears were prepared pre-treatment and 3, 14 and 28 days after starting chemotherapy. Parasitaemias were determined after staining the smears with Giemsa's stain. Blood samples from the patients who were not smear-negative by day 3 were carefully checked for parasites, by staining smears with Acridine Orange and by a PCR-based assay. Only two of the patients appeared to be parasitaemic on day 14 and were therefore considered treatment failures. Although both were apparently cured after additional therapy with the same regimen, one had a recurrence 8 months later. Most cases of recent, resurgent malaria in South Korea therefore appear to sensitive to chloroquine.

A new autoantigen reactive with prediabetic nonobese diabetic mice sera

The identification and characterization of new autoantigens would widen the knowledge of the pathogenic mechanism of insulin dependent diabetes mellitus. Screening of lambda gt11 mouse insulinoma (MIN6N8a) cell cDNA library with prediabetic nonobese diabetic (NOD) mice sera resulted in the isolation of a strong positive clone, named the clone 3-5, of 1579 nucleotides without a poly A region. After 5'-rapid amplification of the cDNA end (RACE), complete nucleotide sequence of the clone 3-5 gene consisting of 2231 nucleotides showed that the 3-5 gene had the theoretical open reading frame of 634 amino acids. However, the real antigenic protein of the clone 3-5 was only 21 amino acids long encoded by only 63 nucleotides. The 21 amino acids were expressed as a fusion protein in E. coli and purified by affinity chromatography. The purified 3-5 recombinant protein was examined for its reactivity with prediabetic NOD mice sera by immunoblotting. The only non-denatured form of the 3-5 protein showed a binding reactivity with NOD mice sera, demonstrating that the conformational epitope of 3-5 protein was important for antibody recognition. The prevalence of autoantibody reactive to the 3-5 protein was about 78% (14/18) and 46% (11/24) in prediabetic and acute diabetic NOD mice sera, respectively. However, the sera from other mouse strains such as BALB/c, ICR, C57BL/6, SJL/J, and NOD/SCID did not show a positive reactivity to the 3-5 protein, which indicated that immune reactivity against the 3-5 protein was autoimmune diabetic mouse-specific.

Cloning and characterization of the gene encoding Aspergillus nidulans DNA topoisomerase II

We have determined the complete nucleotide sequence of a 5544bp genomic DNA fragment from Aspergillus nidulans that encodes DNA topoisomerase II (topo II). It contains a single open reading frame of 4740bp that codes for 1579 amino acid residues with a molecular weight of 178kDa; when expressed in Escherichia coli and Saccharomyces cerevisiae the molecular weight was 180kDa. The gene (TOP2) is divided into three exons. Two introns, 54bp and 60bp in length, are located at nucleotide positions 187 and 3214 respectively. Comparison of the deduced amino acid sequence with other eukaryotic topo II sequences showed a higher degree of identity with other fungal enzymes than the human topo IIalpha. One of monoclonal antibodies raised against human topo II, 6H8, can cross-react with Aspergillus topo II.

Synthesis and evaluation of 2-amino-9-(3-acyloxymethyl-4-alkoxycarbonyloxybut-1-yl)purines and 2-amino-9-(3-alkoxycarbonyloxymethyl-4-alkoxycarbonyloxybut-1- yl)purines as potential prodrugs of penciclovir

A series of 2-amino-9-(3-acyloxymethyl-4-alkoxycarbonyloxybut-1-yl)purin es (1-8) and 2-amino-9-(3-alkoxycarbonyl-oxymethyl-4-alkoxycarbonyloxybut -1-yl)purines (9-12) were synthesized as potential prodrugs of penciclovir. Treatment of 6-deoxypenciclovir with trimethyl orthoacetate or triethyl orthopropionate (1.2 equiv) in DMF in the presence of p-TsOH.H2O (0.1 equiv) followed by quenching with excess H2O gave the corresponding mono-O-acetyl or mono-O-propionyl compound, 17 or 18, in excellent yields of 95 and 92%, respectively. Reactions of 17 or 18 with an appropriate alkyl (Me, Et, n-Pr, and i-Pr) 4-nitrophenyl carbonate (1.2 equiv) in pyridine in the presence of a catalytic amount of DMAP (0.1 equiv) at 80 degrees C afforded the monoacyl, monocarbonate derivatives of 6-deoxypenciclovir, 1-8, in 86 94% yields. Similar reactions of 6-deoxypenciclovir with 2.1 equiv of alkyl 4-nitrophenyl carbonate produced the dicarbonate derivatives 9 12 in 81-83% yields. Of the prodrugs tested in rats, 2-amino-9-(3-acetoxymethyl-4-isopropoxycarbonyloxybut-1-yl)purine (4) achieved the highest mean urinary recovery of penciclovir (36%), followed in order by compounds 2 (35%), 6 (35%), 7 (34%), 10 (34%), 8 (32%), 3 (32%), and famciclovir (31%). The mean urinary recovery of penciclovir and concentrations of penciclovir in the blood from 4 in mice were also slightly higher than those from famciclovir. The in vivo antiviral efficacy of 4 in HSV-1-infected normal BALB/c mice was higher than those of famciclovir and valaciclovir in terms of mortality (100, 80, and 40%) and mean survival time ( > 21, 13+/-5.0 (SEM), and 13+/-1.6 days). Compound 4 demonstrated an effective anti-hepadnaviral response with intrahepatic viral load being reduced by 90%, the viral supercoiled DNA levels reduced by 70% and Pre-S expression inhibited by 30% against duck hepatitis B virus (DHBV) in vivo, and did not cause any significant hepatotoxicity after 4 weeks of treatment.

Restoration of a stem-loop structure required for potato virus X RNA accumulation indicates selection for a mismatch and a GNRA tetraloop

The 5' region of potato virus X (PVX) RNA contains a stem-loop structure, stem-loop 1 (SL1), that is required for efficient plus-strand RNA accumulation. To determine how changes to individual elements in SL1 are accommodated by the virus, we inoculated PVX transcripts containing modifications in the terminal tetraloop (TL), stem C (SC), and stem D (SD) regions onto Nicotiana benthamiana plants and analyzed progeny RNAs over a series of passages. Several progeny RNAs isolated from plants inoculated with the TL mutants containing changes to the first nucleotide of the GAAA motif or deletion of the entire TL sequence were found to contain multiple A insertions within the terminal loop region. The wild-type TL motif, GAAA, was recovered for all TL mutants by the second passage, suggesting that the sequence and potential structure of this element are crucial for PVX infection. Revertant RNAs isolated from plants inoculated with mutants in SD and the central region of SC indicated that increased stem length is tolerated. Restoration of SD length to the 4 bp typical of the wild-type PVX RNA was accompanied by A insertion into loop C. Mutants with a conversion of the C55-C78 mismatch to a G-C pair, relocation of this mismatch within the central region of SC, or deletion of C55-C78 were unable to infect protoplasts and plants. In contrast, the mutant with a conversion of the C55-C78 mismatch to an A-C mismatch, which exhibited low levels of PVX plus-strand RNA in protoplasts, was able to infect plants and quickly reverted to the wild-type C-C mismatch. These data indicate that important sequence and secondary structural elements within SL1 are required for efficient viral infection and that multiple A insertions within the TL and loop C regions, potentially by polymerase stuttering, accompany restoration of SL1 structure.

The infusion rate of mivacurium or atracurium for cesarean section compared with gynecological procedures

Mivacurium is mainly metabolized by plasma cholinesterase, whereas atracurium is removed by Hofman elimination. The purpose of this study was to compare the infusion rate of atracurium and mivacurium in maintaining surgical relaxation, and to compare their recovery indices between parturients and non-pregnant women. Muscle relaxation was maintained by the continuous infusion of relaxants to retain the first response of train-of-four (TOF) at 5% of control. When mivacurium was used, Bolus-T5 (duration from the end of mivacurium bolus injection to 5% single twitch recovery) was measured. After discontinuing the infusion, the recovery index was measured. The infusion rate of mivacurium, not atracurium, was significantly lower in parturients and Bolus-T5 of parturients was significantly longer than that of non-pregnant women. There was no significant difference in the recovery indices of both relaxants. The authors concluded that the infusion rate of mivacurium in maintaining muscle relaxation in parturients should be reduced compared to the rate in non-pregnant women and measuring Bolus-T5 may be helpful in determining the infusion rate to maintain muscle relaxation.

Helical periodicity of (PNA)2.(DNA) triplexes in strand displacement complexes

To study the helical structure in a P-loop formed by an invasion of oligopyrimidine peptide nucleic acid (PNA) into DNA duplex, bent DNA fragments containing a homopurine.homopyrimidine sequence between two bent DNA loci were prepared. As the spacer DNA length between the two bent loci varied by 1 bp over one helical turn, the electrophoretic mobility, reflecting the overall extent of DNA bending, was modulated sinusoidally in non-denaturing 5% polyacrylamide gel. When the bent DNA fragments differing in the spacer DNA length were preincubated with an oligopyrimidine PNA, the gel mobilities were changed due to a P-loop formation. By analyzing the gel mobility data with variations of the P-loop size, average helical parameters at the P-loop structure were determined. (PNA)2. (DNA) triplex within a P-loop had the helical periodicities of 15. 6(0.2) bp per turn at 20 degrees C and 17.4(0.7) bp per turn at 10 degrees C. In addition, the results indicate that a helical unwinding by 57(7) degrees at 20 degrees C and 37(13) degrees at 10 degrees C is present at the two junctions between a P-loop and its adjacent DNA duplex.

Nicotine-enhanced epithelial differentiation in reconstructed human oral mucosa in vitro

Oral mucosal keratinocytes represent the cells that first encounter tobacco components. Therefore, tobacco-induced abnormal alteration of the mucosal keratinocytes may contribute to the development of oral white lesions. Nicotine is an ingredient of all tobacco products and pharmacologically the most active component of tobacco smoke. To clarify the effects of nicotine on the keratinization of oral mucosal and epidermal keratinocytes, we reconstructed artificial buccal mucosal and skin equivalents using keratinocytes and fibroblasts from noncornifying buccal mucosa and adult foreskin, respectively. The effect of nicotine on keratinization was assessed with morphology, immunohistochemistry and immunoblotting. Long-term treatment with nicotine for 2 weeks enhanced in a dose-dependent manner the expression of differentiation-specific proteins of oral mucosal keratinocytes on living oral mucosal equivalent and epidermal keratinocytes on living skin equivalent, respectively. The effect of nicotine on the cell viability was measured by the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. Oral mucosal keratinocytes showed a higher resistance to nicotine toxicity than epidermal keratinocytes. Our results suggest that nicotine stimulates differentiation of both mucosal and epidermal keratinocytes, and this nicotine-induced abnormal differentiation may be associated with the development of oral white lesions.

Mucormycosis of the central airways: CT findings in three patients

Computed tomographic (CT) findings are described in three diabetic patients with central airways mucormycosis. The CT findings of the tracheobronchial mucormycosis include enhancing areas of mural thickening (n = 3), luminal narrowing (n = 3), intramural air (n = 3), low-attenuation nonenhancing bronchial wall thickening (n = 2), and bronchonodal fistula formation (n = 1). These CT features in a diabetic patient should raise a high index of suspicion for tracheobronchial mucormycosis, particularly when typical radiographic features of pulmonary tuberculosis are absent.

Fas receptor up-regulation and membrane localization concurrent with apoptosis in idiopathic esophageal ulceration: toward a better understanding of esophageal injury in AIDS

Activation of the Fas-mediated apoptotic pathway in the etiology of idiopathic esophageal ulcerations (IEUs) was investigated. Constitutive expression of Fas ligand (Fas L) was found in the basal layer of the normal esophageal mucosa and in IEUs and cytomegalovirus ulcerations. In addition to an altered cytokine environment, there was significant up-regulation of Fas antigen mRNA and membrane localization of the receptor in IEU specimens. Concomitant increase in the basic components of Fas machinery, together with elevated mucosal apoptosis, strongly suggests the potential role of the Fas signaling pathway in the onset of tissue destruction associated with IEUs.

Development of videostrobokymography for the quantitative analysis of laryngeal vibratory pattern

We developed a new analysis technique for the assessment of irregular vibratory movement of vocal folds. Successive frames of pre-recorded video images from videostroboscopy were transferred to computer memory and vibratory track of one selected point was described as a waveform by displaying the same lines of all frames along the vertical direction. Glottal area waveform, which was normalized with glottal length, was composed to quantitatively assess the overall vibratory pattern of vocal folds. By applying this technique, irregular vibratory patterns of multiple regions, such as asynchronized registration of glottal cycles, could be easily visualized. It would be possible to monitor and analyze the pathologic changes of vocal fold movement by means of this newly developed system.

Arachidonic acid induces the activation of the stress-activated protein kinase, membrane ruffling and H2O2 production via a small GTPase Rac1

Arachidonic acid (AA) is generated via Rac-mediated phospholipase A2 (PLA2) activation in response to growth factors and cytokines and is implicated in cell growth and gene expression. In this study, we show that AA activates the stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) in a time- and dose-dependent manner. Indomethacin and nordihydroguaiaretic acid, potent inhibitors of cyclooxygenase and lipoxygenase, respectively, did not exert inhibitory effects on AA-induced SAPK/JNK activation, thereby indicating that AA itself could activate SAPK/JNK. As Rac mediates SAPK/JNK activation in response to a variety of stressful stimuli, we examined whether the activation of SAPK/JNK by AA is mediated by Rac1. We observed that AA-induced SAPK/JNK activation was significantly inhibited in Rat2-Rac1N17 dominant-negative mutant cells. Furthermore, treatment of AA induced membrane ruffling and production of hydrogen peroxide, which could be prevented by Rac1N17. These results suggest that AA acts as an upstream signal molecule of Rac, whose activation leads to SAPK/JNK activation, membrane ruffling and hydrogen peroxide production.

Establishment and characterization of human laryngeal squamous cell carcinoma cell lines

OBJECTIVES

Six human laryngeal squamous cell carcinoma cell lines (SNU-46, -585, -899, -1066, -1076, -1214) established from Korean patients are reported.

STUDY DESIGN

In vitro culture of six squamous cell carcinoma cell lines derived from primary tumors of the larynx. Description of the cell line phenotypes and determination of molecular characteristics.

METHODS

Six laryngeal squamous cell carcinoma cell lines were cultured. The cell phenotypes, including the histopathology of the primary tumors and in vitro growth characteristics, were determined. Molecular characterization was also performed, including DNA fingerprinting analysis and abnormalities of p15, p16, p53, and TGF-betaRII genes by polymerase chain reaction-based single strand conformation polymorphism and sequencing analysis.

RESULTS

All cell lines grew as adherent cells; five lines grew as monolayers and one other line grew as stratifying colonies. All lines showed 1) high viability (75%-92%) with various doubling times (36-96 h); 2) absence of Mycoplasma and other bacteria; and 3) genetic heterogeneity by DNA profile analysis. p53 Mutations were found in three lines and p16 mutations were observed in five cell lines. TGF-betaRII mutations were found in two lines: one line had frameshift mutation and another line had a missense mutation at the kinase domain.

CONCLUSIONS

These newly established and characterized laryngeal squamous cell carcinoma cell lines will be useful for investigating the biologic characteristics of laryngeal cancer.

Crescentic glomerulonephritis: a clinicopathologic analysis of 17 cases with emphasis on glomerular and interstitial neutrophil infiltration

In order to determine the extent to which specific forms of glomerulonephritis (GN) contribute to the pool of crescentic GN, renal tissues from 17 crescentic GN patients were examined with special attention to glomerular and interstitial neutrophil infiltration. Renal tissues from five normal kidneys served as normal controls. Renal biopsy tissues from five patients with postinfectious GN in which crescent formation was not observed were also examined as disease controls. The patients were put into both three groups according to immunofluorescence findings and two groups according to the active or inactive phase of the crescents: group 1 with anti-glomerular basement membrane crescentic GN, one case; group 2 with immune complex crescentic GN, ten cases; and group 3 with pauci-immune crescentic GN, six cases. Four of the nine individuals tested were positive for anti-neutrophil cytoplasmic antibody (44.4%). Glomerular and interstitial neutrophil infiltrations were prominent in both the active and inactive phase groups, compared to normal controls (p<.05). Glomerular neutrophil infiltration was significantly prominent in the active phase group, compared to the inactive phase group (p<.001). In both the active and inactive phase groups, interstitial neutrophil infiltration was prominent, compared to disease control groups (p<.05). These results support the concept of the participation of periglomerular leukocytes in the renal tissue damage of crescentic GN, although the role of neutrophils was not examined.

Soluble expression in Escherichia coli of murine endogenous retroviral transmembrane envelope protein having immunosuppressive activity

Recently, we cloned a fragment of the endogenous murine leukemia viral envelope gene from beta cell line (MIN6N8a) as a new autoantigen gene, whose product was reactive with nonobese diabetic (NOD) mice sera. As a result of determination of nucleotide sequence, this envelope protein had the CKS-17 peptide sequence having immunosuppressive activity. To investigate the role of our cloned transmembrane envelope protein in the pathogenesis of autoimmune insulin-dependent diabetes mellitus (IDDM) as an autoantigen or immunosuppressive modulator, a high amount of transmembrane envelope protein was essentially required. Therefore, the expression of our cloned retroviral transmembrane envelope gene was tried in Escherichia coli by a pET vector. However, the expression rate was very low (less than 2%) and most of the expressed protein was insoluble. To improve solubility, the hydrophobic transmembrane anchor domain of our envelope gene was deleted and then the expression of the hydrophilic transmembrane envelope protein was carried out by using the same pET expression system. The expressed protein was completely soluble and the expression yield was dramatically improved by around 25-fold increase. The hydrophilic transmembrane envelope protein was purified by one-step Ni-NTA affinity chromatography and then the fusion tag consisting of the six-histidine peptide and S peptide was removed by cleavage with enterokinase. The processed hydrophilic retroviral transmembrane envelope protein was still immune reactive with NOD sera and also showed immunosuppressive activity by down-regulating the Th1-type cytokine (interferon-gamma) and up-regulating the Th2-type cytokine (interleukin 10).

Isolation and characterization of the Saccharomyces cerevisiae EKI1 gene encoding ethanolamine kinase

Ethanolamine kinase (ATP:ethanolamine O-phosphotransferase, EC 2.7.1. 82) catalyzes the committed step of phosphatidylethanolamine synthesis via the CDP-ethanolamine pathway. The gene encoding ethanolamine kinase (EKI1) was identified from the Saccharomyces Genome Data Base (locus YDR147W) based on its homology to the Saccharomyces cerevisiae CKI1-encoded choline kinase, which also exhibits ethanolamine kinase activity. The EKI1 gene was isolated and used to construct eki1Delta and eki1Delta cki1Delta mutants. A multicopy plasmid containing the EKI1 gene directed the overexpression of ethanolamine kinase activity in wild-type, eki1Delta mutant, cki1Delta mutant, and eki1Delta cki1Delta double mutant cells. The heterologous expression of the S. cerevisiae EKI1 gene in Sf-9 insect cells resulted in a 165,500-fold overexpression of ethanolamine kinase activity relative to control insect cells. The EKI1 gene product also exhibited choline kinase activity. Biochemical analyses of the enzyme expressed in insect cells, in eki1Delta mutants, and in cki1Delta mutants indicated that ethanolamine was the preferred substrate. The eki1Delta mutant did not exhibit a growth phenotype. Biochemical analyses of eki1Delta, cki1Delta, and eki1Delta cki1Delta mutants showed that the EKI1 and CKI1 gene products encoded all of the ethanolamine kinase and choline kinase activities in S. cerevisiae. In vivo labeling experiments showed that the EKI1 and CKI1 gene products had overlapping functions with respect to phospholipid synthesis. Whereas the EKI1 gene product was primarily responsible for phosphatidylethanolamine synthesis via the CDP-ethanolamine pathway, the CKI1 gene product was primarily responsible for phosphatidylcholine synthesis via the CDP-choline pathway. Unlike cki1Delta mutants, eki1Delta mutants did not suppress the essential function of Sec14p.

A novel HLA-DR12 allele (DRB1*1206) found in a Korean B-cell line

At least 6 HLA-DRB1*12 alleles have been identified to date with nucleotide polymorphism occurring at codons 37, 57-58, 60, 67, 85 and 87. In this report, we describe the identification of another new HLA-DRB1*12 allele: DRB1*1206. This novel allele was found in an Epstein-Barr virus (EBV)-transformed Korean B-cell line "K-KT" having the HLA-phenotype A3, 24; B44, 61; Cw3; Bw4, 6; DR12, 13 during full-length cDNA isolation for cell line characterization and for production of HLA-DR recombinant proteins. The allele was identified initially by cycle sequencing of subcloned HLA-DRB full-length cDNA.