Dietary threonine prevented stress-related mucosal diseases in rats.

Stress-related mucosal disease (SRMD), or stress ulceration, is a group of conditions ranging from stress-related superficial gastric mucosal damage to deep gastric ulcers that are primarily correlated with mucosal ischemia, and pharmacologic interventions that optimize tissue perfusion or preserve defensive mucus aim to decrease the occurrence of conditions, such as gastric acidity, or enhance gastric defenses. However, the identification of multifactorial pathogenesis may be effective in preventing SMRD, and the use of stress prophylaxis is generally preferred. Since threonine is a component in the polymerization and synthesis of gastric mucin and possibly enhanced defense actions and lignin may provide structural support for defense and antioxidative function, we hypothesized that dietary intake of threonine and/or lignin can enhance defense against SRMD. The water immersion-restraint stress (WIRS) was used in rats and additional groups were pretreated with threonine alone or the combination of threonine and lignin. Based on gross and microscopic evaluations, threonine alone or the combination of threonine and lignin, a natural antioxidant, significantly reduced the development of SRMD (P < 0.05). According to molecular explorations, the levels of inflammatory mediators, such as interleukin (IL)-8, IL-6, IL-1ß, inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF-α), and interferon gamma (IFN-γ), all of which are mediators that play a significant role in controlling WIRS, significantly decreased in the groups pretreated with either threonine alone or the combination of threonine and lignin (P < 0.01). WIRS significantly increased apoptosis in the stomach. However, the apoptotic index significantly decreased with threonine pretreatment. According to periodic acid Schiff staining results, the expression of gastric mucin was significantly preserved in groups pretreated with threonine but remarkedly decreased in the WIRS group. The gastric heme oxygenase-1 levels significantly increased in the group treated with threonine. In conclusion, the dietary intake of threonine or the combination of threonine and lignin is effective in preventing SRMD.

Walnuts (seeds of Juglandis sinensis L.) protect human epidermal keratinocytes against UVB-induced mitochondria-mediated apoptosis through upregulation of ROS elimination pathways.

PURPOSE: Ultraviolet (UV) light from sunlight is an important environmental factor causing hazardous health effects, including various skin disorders. UV irradiation downregulates reactive oxygen species (ROS) elimination pathways, thereby promoting the production of ROS, which are implicated in mitochondria-mediated apoptosis. Walnuts, the seeds of Juglandis sinensis L., are a highly nutritious food and have been shown to have a number of pharmacological activities. To our knowledge, no study on the protective effects of walnuts on human epidermal keratinocytes has been reported previously. Here, we investigated the protective effects of walnuts against UVB (50 mJ/cm(2)) -induced mitochondria-mediated apoptosis. PROCEDURES AND RESULTS: Walnuts significantly and dose-dependently reduced UVB-induced apoptotic toxicity by lactate dehydrogenase assay kit. Walnuts decreased mitochondrial dysfunction, B-cell lymphoma 2 (Bcl-2)-associated X (Bax) protein levels, and cytochrome c release from mitochondria, while increasing Bcl-2 protein levels using immunofluorescence, Western blot, or kit analysis. Moreover, walnuts inhibited caspase-3 activity, indicating an inhibition of the apoptotic cascade, and induced the expression of heme oxygenase and NAD(P)H dehydrogenase via NF-E2-related factor-2 activation using immunofluorescence or Western blot analysis. CONCLUSION: Together, these results demonstrate that walnuts can protect human epidermal keratinocytes against UVB-induced mitochondria-mediated apoptosis by regulating ROS elimination pathways.

Leiomyosarcoma of the pulmonary veins extending into the left atrium.

Primary tumors of the great vessels are very rare. Primary leiomyosarcomas of the pulmonary vein are extremely rare and little is known about their clinical manifestation and treatment. We report the case of a 34-year-old patient with primary leiomyosarcoma of the pulmonary vein extending into the left atrium. A review of the clinical manifestation and treatment of 24 cases including our own is provided.

Gastrin promotes intestinal polyposis through cholecystokinin-B receptor-mediated proliferative signaling and fostering tumor microenvironment.

Increased serum gastrin concentrations in patients with colorectal cancer suggested the tumorigenic trophic effect of gastrin. Detailed and global molecular mechanisms explaining trophic effect of gastrin had not been revealed. In the current study, intestinal polyposis of APC(Min/⁺) mice was compared between phosphate buffered saline (PBS) injected and gastrin (10 µg/kg, thrice per week) injected group. Total number of intestinal polyposis was counted and immunohistochemical staining with F4/80 and CD3 was done. MTT assay, cell cycle analysis, and Western blot for cyclin D1, CDK4, and ß-catenin were performed in Raw 264.7 and HCT116 cells before and after gastrin administration. Experiments were repeated with YM022 or transfection with si-cholecystokinin-B receptor (CCK-B-R). Intraperitoneal gastrin significantly increased intestinal polyposis in APC(Min/⁺) mice (P<0.005), in which significant increases in macrophage were noted on F4/80 immunohistochemical staining (Plt;0.05) as well as Ki-67 staining (Plt;0.05) after gastrin. On comparative cytokine array, gastrin increased interleukin-1ß (IL-1ß), interleukin 3Rß (IL-3Rß), stromal cell-derived factor-1α (SDF-1α), thymus and activation-regulated chemokine (TARC), and thymus-derived chemotactic agent 3 (TCA-3) in macrophage cells, which was further confirmed with real time polymerase chain reaction (RT-PCR) analysis (P<0.05). In addition to increased inflammatory cytokines, gastrin increased macrophage proliferation accompanied with increased cyclin D1 and CDK4. Targeted for HCT116 cells, gastrin significantly increased proliferation as well as increases in synthetic phase of cell cycle. YM022 as gastrin antagonist significantly abolished the trophic actions of gastrin (P<0.05). HCT116 cells transfected with siCCK-B-R, gastrin did not increase either cell cycle or ß-catenin in spite of gastrin administration. Conclusively, gastrin promoted intestinal polyposis through either direct gastrin receptor-mediated proliferative signaling or fostering tumor microenvironment such as macrophage activation.

Detection of ABL1 kinase mutations in Philadelphia-positive patients exhibiting an inadequate molecular response using restriction fragment mass polymorphism and its clinical significance: a single-center experience in Korea.

INTRODUCTION: ABL1 kinase mutations represent a major mechanism of imatinib resistance in Philadelphia-positive (Ph+) patients. There is a paucity of data on ABL1 kinase mutations in Ph+ patients in Korea. METHODS: We used restriction fragment mass polymorphism (RFMP) analysis to detect ABL1 kinase mutations in blood or bone marrow specimens from 80 Ph+ patients. RESULTS: Fifty-seven patients met the criteria for inadequate molecular response (IMR). ABL1 kinase mutations were found in 2.6% of patients with chronic-phase chronic myelogenous leukemia (CML), 25.0% of accelerated-phase CML, 66.7% of blast-phase CML, and in 58.3% with Ph+ acute lymphoblastic leukemia. Twelve mutations were identified: 7 T315I, 2 E255V, 1 E255K, 1 F359V, and 1 Y253H. The majority of mutation-positive patients showed an unfavorable clinical course and often had an extra Ph or additional chromosomal abnormalities. Mutations were detected in two patients who had very low or absent BCR-ABL1 normalized ratios. CONCLUSION: Mutation analysis should be performed in Ph+ patients exhibiting an IMR to imatinib. RFMP analysis is helpful for revising therapeutic strategies because it can sensitively detect clinically relevant ABL1 kinase mutations with high frequencies.

Clinical outcomes and risk factors of post-polypectomy coagulation syndrome: a multicenter, retrospective, case-control study.

BACKGROUND AND STUDY AIMS: Post-polypectomy coagulation syndrome (PPCS) is a well known complication of colonoscopic polypectomy. However, no previous studies have reported on the clinical outcomes or risk factors of PPCS. The aim of the current study was to analyze the clinical outcomes and risk factors of PPCS developing after a colonoscopic polypectomy. PATIENTS AND METHODS: Data for all patients who underwent colonoscopic polypectomies and required hospitalization in nine university hospitals were analyzed retrospectively. The incidence, clinicopathological characteristics, and clinical outcomes of PPCS cases were examined. Additionally, patients who developed PPCS were compared with controls who were matched by age and sex, in order to assess for possible risk factors. RESULTS: The rate of PPCS that required hospitalization after colonoscopic polypectomy was 0.7/1000. All patients with PPCS were treated medically without the need for surgical interventions. The median durations of therapeutic fasting, hospitalization, and antibiotic use were 3 days, 5.5 days, and 7 days, respectively. The rates of major PPCS and mortality were 2.9 % and 0 %, respectively. On multivariate analysis, hypertension (OR = 3.023, 95 %CI 1.034 - 8.832), large lesion size (OR = 2.855, 95 %CI 1.027 - 7.937), and non-polypoid configuration (OR = 3.332, 95 %CI 1.029 - 10.791) were found to be independent risk factors related to the development of PPCS. CONCLUSIONS: In this study, the rates of major PPCS and mortality were only 2.9 % and 0 %, respectively. Hypertension, large lesion size, and non-polypoid configuration of the lesion were independently associated with PPCS. Therefore, patients may be reassured by the excellent prognosis of PPCS, while endoscopists should be especially careful when performing colonoscopic polypectomies in patients with hypertension or large and non-polypoid lesions.

Recurrent deep vein thrombosis and pulmonary embolism in a patient with Klinefelter's syndrome.

Klinefelter's syndrome, which is characterized by small testes, gynecomastia, hypogonadism, and infertility, is the most common cause of primary testicular failure, and commonly has an XXY karyotype. Deep vein thrombosis and thomboembolic events are a rare occurrence in these patients. Although the exact mechanism is not completely understood, it is thought that increased thromboembolic risk in hypogonadic men can be explained by hypofibrinolysis resulting from androgen deficiency. We present the case of a 48-year-old man with Klinefelter's syndrome who experienced recurrent episodes of deep venous thrombosis and pulmonary embolism while undergoing therapeutic anticoagulation. Our report discusses this association and management of the prothrombotic state in patients with Klinefelter's syndrome.

Recurrent odontogenic ghost cell carcinoma (OGCC) at a reconstructed fibular flap: a case report with immunohistochemical findings.

Odontogenic ghost cell carcinoma (OGCC), a malignant counterpart of the odontogenic ghost cell tumor (OGCT), with aggressive growth characteristics, is exceedingly rare. A painful swelling in the jaw with local paresthesia is the most common symptom. We described a case of 47-year Korean woman who had a rare central epithelial odontogenic ghost cell carcinoma which recurred at reconstructed fibular flap. Immunohistochemical differences between OGCT and OGCC analyzed using primary and recurred surgical specimen. On the basis of this case, the tumor started as an OGCT and transformed into OGCC with highly aggressive, rapidly growing, infiltrative tumors. Our findings suggest that some of the cytokines produced by ghost cells may play important roles in causing extensive bone resorption in the odontogenic ghost cell carcinoma. Wide local excision with histologically clean margins is the treatment mode of selection. Also, we recommend close long-term surveillance of OGCT because of high recurrence and potential for malignancy transformation.

Production of transgenic recloned piglets harboring the human granulocyte-macrophage colony stimulating factor (hGM-CSF) gene from porcine fetal fibroblasts by nuclear transfer.

We used nuclear transfer (NT) to develop transgenic female pigs harboring goat beta-casein promoter/human granulocyte-macrophage colony stimulating factor (hGM-CSF). The expression of hGM-CSF was specific to the mammary gland, and the glycosylation-derived size heterogeneity corresponded to that of the native human protein. Although various cell types have been used to generate cloned animals, little is currently known about the potential use of fibroblasts derived from a cloned fetus as donor cells for nuclear transfer. The developmental potential of porcine cloned fetal fibroblasts transfected with hGM-CSF was evaluated in the present study. Cloned fetal fibroblasts were isolated from a recipient following the transplantation of NT embryos. The cells were transfected with both hGM-CSF and the neomycin resistance gene in order to be used as donor cells for NT. Reconstructed embryos were implanted into six sows during estrus; two of the recipient sows delivered seven healthy female piglets with the hGM-CSF gene (confirmed with PCR and fluorescent in situ hybridization) and microsatellite analysis confirmed that the clones were genetically identical to the donor cells. The expression of hGM-CSF was strong in the mammary glands of a transgenic pig that died a few days prior to parturition (110 d after AI). These results demonstrated that somatic cells derived from a cloned fetus can be used to produce recloned and transgenic pigs.

Weekly full-dose gemcitabine and single-dose cisplatin with concurrent radiotherapy in patients with locally advanced pancreatic cancer.

The aim of this study was to evaluate the efficacy and the toxicity of a full dose of gemcitabine and a single dose of cisplatin with concurrent radiotherapy in patients with locally advanced pancreatic cancer. Forty-one patients with locally advanced pancreatic cancer were enrolled. Patients received gemcitabine (1000 mg m(-2) on days 1, 8, 15, 29, and 36) and cisplatin (70 mg m(-2) on days 1 and 29) with concurrent radiotherapy (45 Gy in 25 fractions). Treatment was completed in 38 out of 41 patients (92.7%). The overall response rate was 24.4% (two complete and eight partial). Six patients (14.6%) underwent definite pancreatic resection and four had negative surgical margins. The intention of the treatment analysis showed that the median survival time and median time to tumour progression were 16.7 and 8.9 months. The 1- and 2-year survival rates were 63.3 and 27.9%, respectively. Overall survival was significantly longer in the low baseline CA19-9 group and therapeutic responders. Toxicities were tolerable and successfully managed by conservative treatments. The therapeutic scheme of a weekly full dose of gemcitabine and a single dose of cisplatin combined with external radiation is effective and might prolong the survival of patients with locally advanced pancreatic cancer.

Prognostic value of activated Akt expression in oral squamous cell carcinoma.

BACKGROUND: Akt is a serine/threonine kinase that plays an important role in tumorigenesis and influences prognosis in several cancers. However, its importance in oral squamous cell carcinomas (OSCC) has not been elucidated. AIM: To investigate the association between the expression of activated Akt, clinicopathological factors, and E-cadherin, PCNA (proliferating cell nuclear antigen), and VEGF (vascular endothelial growth factor) expression to verify the validity of Akt as a prognostic factor in OSCC. METHODS: Phosphorylated Akt (p-Akt), E-cadherin, PCNA, and VEGF expression were assessed immunohistochemically in 84 OSCCs. The results were analysed in relation to clinicopathological factors. RESULTS: p-Akt was expressed in 29 cases. It was significantly correlated with lymph node metastasis, TNM stage, and E-cadherin expression. Univariate analysis showed that p-Akt expression, E-cadherin expression, PCNA expression, differentiation, tumour size, lymph node metastasis, TNM stage, and recurrence correlated with prognosis. Multivariate analysis showed that p-Akt expression is an independent prognostic factor in patients with OSCC. CONCLUSIONS: This study revealed that Akt activation is a significant prognostic indicator for OSCC and is correlated with E-cadherin expression. The inhibition of Akt is a possible molecular approach to the treatment of OSCC.

The expression of NMDA receptor 1 is associated with clinicopathological parameters and prognosis in the oral squamous cell carcinoma.

BACKGROUND: Glutamate activates the N-methyl-d-aspartate (NMDA) receptors and this receptor is involved in the proliferation and migration of various tumour cells in vitro. However, the relationship between NMDA receptor expression and clinical parameters in cancer patients is unclear. Therefore, NMDA receptor 1 (NMDAR1) expression along with its clinical significance was examined in patients with oral squamous cell carcinoma (OSCC). METHODS: Eighty-one tumour specimens from OSCC patients were used to determine the NMDAR1 expression level by immunohistochemical staining. The control was obtained from a matched normal adjacent mucosa. The cases were considered to be positive if reactivity was displayed in >25% of the cells. RESULTS: The NMDAR1 reactivity was positive in 50 of 81 cases, while it was negative in the control. NMDAR1 expression was significantly associated with a lymph node metastasis (P = 0.008), the tumour size (P < 0.001), and the cancer stage (P = 0.034). The patients whose tumours expressed NMDAR1 had a significantly poorer survival than the patients who were NMDAR1-negative (log-rank = 6.45, d.f. = 1, P = 0.011). CONCLUSIONS: The NMDAR1 overexpression was significantly associated with the prognosis-related factors. Therefore, it might be one of the prognostic markers of OSCC.

Chiral separation of beta-blockers after derivatization with (-)-alphamethoxy-alpha-(trifluoromethyl)phenylacetyl chloride by gas chromatography.

Gas chromatographic method was investigated for the chiral separation of several beta-blockers(atenolol, betaxolol, bisoprolol, metoprolol and pindolol) using (-)-alpha-methoxy-alpha-(trifluoromethyl)phenylacetyl chloride as a chiral derivatizing agent for amino group. Prior to N-acylation, hydroxyl group was converted into O-silyl ethers by react with N-methyl-N-(trimethylsilyl)trifluoroacetamide. The reaction was selective and rapid and the diastereomeric derivatives were well separated by capillary gas chromatography. (R)-isomers were eluted faster than (S)-isomers when (-)-alpha-methoxy-alpha-(trifluoromethyl)phenylacetyl chloride was used as the chiral derivatizing agent. But in the opposite sequence when (+)-alpha-methoxy-alpha-(trifluoromethyl)phenylacetyl chloride was used. No racemization was found during the reaction.

Physiological and biochemical characteristics of poly gamma-glutamate synthetase complex of Bacillus subtilis.

An enzymatic system for poly gamma-glutamate (PGA) synthesis in Bacillus subtilis, the PgsBCA system, was investigated. The gene-disruption experiment showed that the enzymatic system was the sole machinery of PGA synthesis in B. subtilis. We succeeded in achieving the enzymatic synthesis of elongated PGAs with the cell membrane of the Escherichia coli clone producing PgsBCA in the presence of ATP and D-glutamate. The enzyme preparation solubilized from the membrane with 8 mM Chaps catalyzed ADP-forming ATP hydrolysis only in the presence of glutamate; the D-enantiomer was the best cosubstrate, followed by the L-enantiomer. Each component of the system, PgsB, PgsC, and PgsA, was translated in vitro and the glutamate-dependent ATPase reaction was kinetically analyzed. The PGA synthetase complex, PgsBCA, was suggested to be an atypical amide ligase.

Odontogenic keratocyst: Review of 256 cases for recurrence and clinicopathologic parameters.

Odontogenic keratocyst (OKC) is of particular interest because of its high recurrence rate and aggressive behavior. Two hundred fifty-six cases of OKC were reviewed for the age of the patient at diagnosis, sex of the patient, OKC location, and radiographic findings, and 132 patients with OKC were observed to estimate recurrence, which was analyzed for age, sex, location, and several histopathologic findings. OKCs occurred more frequently in men (58.6%) than in women (41.4%), and they occurred in patients within a wide age range, most commonly in patients in the third decade of life (28.9%), followed by those in the second decade (25.0%); the mean age of patients with OKC was 30.8 years. One hundred ninety-six of the 256 cases (76.5%) occurred in the mandible, and the other 60 cases (23.5%) occurred in the maxilla. The mandibular molar and the premolar areas (51.2%) were the most common sites, and the most frequent clinical manifestations at first admission were swelling, pain, or both (82.4% of total cases). Radiographic impressions included dentigerous cyst (27.3%), OKC (25.4%), primordial cyst (14.8%), ameloblastoma (11.7%), residual cyst (9.8%), and radicular cyst (3.1%). The frequency of recurrence at the follow-up examination was 58.3%. There was no significant difference in the recurrence rate on the basis of the sex of the patient. However, OKCs had a significantly higher recurrence rate in patients in the fifth decade of life than in patients in the other age groups (P = .005).Recurrence rates were significantly dependent on the sites of involvement, and OKCs in the mandibular molar region had significantly higher recurrence rates than those in other sites (P = .001). The histopathologic presence of one or more daughter cysts was significantly related to recurrence (P = .03).

Evaluation of the anti-tumor and anti-angiogenic effect of paclitaxel and thalidomide on the xenotransplanted oral squamous cell carcinoma.

Angiogenesis is an essential process for the growth and invasion of cancer. However, it is uncertain that anti-angiogenic effects can be a major treatment strategy of oral cancer. The aim of this study was to investigate whether thalidomide and paclitaxel, which are known to be potent inhibitors of angiogenesis, have inhibitory effects on the growth of oral squamous cell carcinoma (OSCC) xenotransplanted into nude mice and whether anti-angiogenesis can be included as a major treatment strategy of oral cancer. After human OSCC cell line, KB, was subcutaneously inoculated into 32 nude mice, the volume of tumor was measured every 3 days. When the tumor mass reached 300-500 mm3, thalidomide (200 mg/kg) and paclitaxel (13 mg/kg) were administered into the animals and tumor volume change was checked. The excised tumor masses on the 30th day after administration were frozen and processed for immunohistochemistry using vascular endothelial growth factor (VEGF) and CD31, and for real-time reverse transcription-polymerase chain reaction (RT-PCR). We evaluated VEGF expression and the expression of its mRNA and CD31 for vessel density. Paclitaxel showed an inhibitory effect on the growth of transplanted human OSCC and reduced the immunohistochemical expression of VEGF and CD31 and VEGF mRNA (P<0.01). Thalidomide also lowered remarkably VEGF expression (P<0.01) and CD31 (P<0.01) as well as VEGF mRNA (P<0.05), but it did not show statistically significant inhibitory effect on the tumor growth. These results suggest that the growth of human OSCC is not simply dependent on VEGF-induced angiogenesis and that anti-angiogenic therapy alone is not likely to be effective for the treatment of OSCC, but might be regarded as adjuvant chemotherapeutic strategy.

Nucleotide sequence of envelope protein of Japanese encephalitis virus SA14-14-2 adapted to vero cells.

Live attenuated Japanese encephalitis (JE) virus SA(14)-14-2 produced in primary dog kidney cells (PDK) was adapted to Vero cells. In an effort to gain insight into the molecular basis of the biological characteristics of the SA14-14-2(Vero) strain, the 1500 nucleotide sequence encoding the envelope (E) gene which possesses major neutralizing epitopes was determined and compared with the sequences of two other attenuated JE virus strains, SA14-14-2(PHK) and SA14-14-2(PDK). The amino acid sequence of the C-terminal region (a.a. 280-500) was found to be identical for all three strains, while the N-terminal region (a.a. 1-279) shows sequence variation. The distribution of mutations in the N-terminal region was nearly the same among the three attenuated strains, suggesting that the N-terminal sequences might be related with virus-host cell specificity. However, it was found that Lys and Val (a.a. 138 and 176, respectively), known to be responsible for attenuation, are still conserved in SA(14)-14-2(Vero). Animal testing showed that SA(14)-14-2(Vero) has an attenuation phenotype similar to that of the parent SA(14)-14-2(PDK) strain in mice.

Expression of matrix metalloproteinase-2 and -9 in oral squamous cell carcinomas with regard to the metastatic potential.

In order to evaluate the significance of matrix metalloproteinases (MMPs) in predicting the metastatic potential of oral squamous cell carcinomas (SCCs), we compared MMP-2 and -9 expression in 19 metastasizing oral SCCs with that in 25 non-metastasizing cases by immunohistochemistry and gelatin zymography. Immunohistochemistry showed that increased MMP-2 expression was not significantly related to metastasis; increased MMP-9 expression found in oral SCCs was, however, statistically significant (oral SCCs with metastasis, 73.7%; those without metastasis, 36.0%; P<0.05). Gelatin zymography revealed no significant difference in the activated form of MMP-2 between metastasizing and non-metastasizing oral SCCs. In metastasizing SCCs, on the other hand, increases in the activated form of MMP-9 were significant. These results suggest that oral SCCs express MMP-2 and -9, and that MMP-9 may play a more important role than MMP-2 in the metastasis of oral SCCs to adjacent tissue. An analysis of MMP-9 expression may be useful for predicting the metastatic potential of oral SCCs.

Improved fluorescent determination method of cellular sphingoid bases in high-performance liquid chromatography.

Precolumn orthophthaldehyde (OPA) labeling method of sphingoid bases, sphingosine and sphinganine, was investigated to obtain high fluorescent detectability. In order to improve the fluorescent yield, we investigated the optimal solubility of sphingoid bases for five pre-incubation solvents by incorporating the heating procedure before OPA derivatization. The pre-incubation in ethanol prominently increased the fluorescent peak height of OPA derivative for each sphingoid bases in high performance liquid chromatography. About ten-fold increase of detectability was archived by pre-incubating lipid extracts pellets in ethanol at 60 degrees C for 30 min. Optimal derivatization was performed in 30 min at ambient temperature and the fluorescent intensity of OPA derivative was stable for two weeks at 4 degrees C. The detection limit of sphingosine was 0.1 pmol as injected amount. This method was applied to the determination of cellular sphingosine and sphinganine in various human lung cancer cells. This OPA procedure was prospective to be useful for quantitating the amount of sphingoid bases in other cancer cells.