Sphingolipid metabolic changes during chiral C2-ceramides induced apoptosis in human leukemia cells

N-acetylsphingosine (C2-ceramide) is a synthetic water-soluble ceramide mimicking the activity of natural ceramides. By fixing chiral conformation on carbon numbers 2 and 3 in the ceramide structure, four chiral C2-ceramides naming d-erythro-, l-erythro-, d-threo- and l-threo C2-ceramide were synthesized. We have investigated the chiral effects of these C2-ceramides on the sphingolipid metabolism, particularly on both the sphingolipid biosynthetic pathway and on the degradation pathway. In both HL-60 and U937 cells, the chiral C2-ceramide (10 microM) showed sphingosine accumulation monitored fluoromatrically by a high performance liquid chromatographic separation of the sphingoid bases. Most importantly, in HL-60 cells, l-erythro C2-ceramide induced a 50 fold increase in sphingosine as compared to the control, while l-threo C2-ceramide exhibited a minimal 7-fold increase. In contrast, sphinganine, another sphingoid base, showed less accumulation by any chiral C2-ceramide tested under the same conditions. These results suggested that chiral C2-ceramide primarily acts on the sphingolipid degradation pathway rather than on the sphingolipid biosynthetic route. The strong G0/G1 phase arrest in the cell cycle by treatment of l-erythro C2-ceramide indicates that the blockade of the sphingolipid degradation pathway might be concomitantly involved in the dysfunction of the cell cycle. On the other hand, the fact that all chiral C2-ceramides tested failed to inhibit the activity of sphingosine kinase acting on the removal of sphingosine by producing sphingosine-l-phosphate demonstrates that chiral C2- ceramides may increase sphingosine by activating various ceramidases by which natural ceramides are divided into sphingosine and free fatty acids. However, the precise steps involved in this interaction are still unknown.

Immunostimulatory effects of anionic alkali mineral complex solution Barodon in porcine lymphocytes

The anionic alkali mineral complex solution, Barodon (Barodon-S.F. Corp., Korea), was evaluated for its effectiveness as a nonspecific immunostimulator in pigs. The effects of Barodon were determined by analysis of feed efficiency, growth rate, and phenotype of leukocyte subpopulations using monoclonal antibodies specific to porcine leukocyte differentiation antigens and flow cytometry (FC). The study was focused to investigate the change in proportion of the CD4+CD8+ double positive T lymphocyte subpopulation (dpp) which exists uniquely in pigs. In addition, the mitogen-stimulated lymphoproliferative response, tissue distribution in lymphoid organs and the adjuvant effect of Barodon on hog cholera vaccine efficiency were determined. The study has revealed the average daily gain rates and feed conversion rates were significantly (p<0.05) improved in either group of pigs fed with 0.05% Barodon-spray feed (Tx-1) or pigs fed with 3% Barodon-fermented feed (Tx-2) in comparison with group of pigs fed with feed containing no Barodon (control). The proportion of cells expressing CD4+ antigen in Barodon-treated group increased from 3 weeks posttreatment and was significantly higher (p<0.05) than that of control at 8 weeks posttreatment. Particularly, the significantly higher proportion was maintained from 8 weeks through 13 weeks posttreatment in Tx-1 group (p<0.05). The proportion of cells expressing CD8+ antigen was significantly higher at 3 weeks posttreatment in Tx-2 (p<0.01). Proportion of MHC class II-expressing cells was significantly higher in Tx-1 and Tx-2 group at 11 weeks and 8 weeks posttreatment (p<0.05), respectively. In addition, the proportion of Non T/Non B (N) cells was also significantly higher in Tx-2 at 3 weeks posttreatment (p<0.01) and maintained to 13 weeks posttreatment (p<0.1). Between Barodon-treated groups, the proportion of MHC class II-expressing cells was observed to be larger in Tx-2 than Tx-1 from 3 weeks to 8 weeks posttreatment (p<0.05). However, there were no significant difference in the proportions of CD2+ cells, B cells, monocytes and granulocytes between Barodon-treated and control group during the experiment. Dual-color FC analysis, study has revealed an increased proportion of dpp present in lymphocytes obtained from peripheral blood (PB) and mesenteric lymph node (MLN) of Barodon-treated group at 8 and 11 weeks posttreatment. The proportion of dpp in PB was 27.5% and 32.1% in Tx-1 and Tx-2, respectively, but only 2.2% in control group at 8 weeks posttreatment. In MLN, the proportion was 45.1% and 52.1% in Tx-1 and Tx-2, respectively, otherwise 16.5% in control group at 8 weeks posttreatment. The mitogen-stimulated activity was significantly higher in Tx-1 than in the control group at 11 weeks posttreatment when cells were stimulated with Con A and PHA, respectively (p<0.01). Also, Con A-, PHA and PWM-stimulated activity was significantly higher in Tx-2 than in the control group at the same time (p<0.05). The tissue distribution of CD4+, CD8+ and CD4+CD8+ dpp in MLN and spleen was significantly larger in Tx-1 and Tx-2 than in the control group (p<0.01). Also, a larger proportion of dpp was observed in Tx-2 than Tx-1 in spleen between Barodon-treated groups (p<0.01). In conclusion, the study has demonstrated that Barodon had an immunostimulatory effect on pigs through proliferation and activation of porcine immune cells, specially CD4+CD8+ dpp lymphocytes.

Detection of canine distemper virus (CDV) through one step RT-PCR combined with nested PCR

A one step reverse transcription PCR (RT-PCR) combined nested PCR was set up to increase efficiency in the diagnosis of canine distemper virus (CDV) infection after developement of nested PCR. Two PCR primer sets were designed based on the sequence of nucleocapsid gene of CDV Onderstepoort strain. One-step RT-PCR with the outer primer pair was revealed to detect 10(2) PFU/ml. The sensitivity was increased hundredfold using the one-step RT-PCR combined with the nested PCR. Specificity of the PCR was also confirmed using other related canine virus and peripheral blood mononuclear cells (PBMC) and body secretes of healthy dogs. Of the 51 blood samples from dogs clinically suspected of CD, 45 samples were revealed as positive by one-step RT-PCR combined with nested PCR. However, only 15 samples were identified as positive with a single one step RT-PCR. Therefore approximately 60% increase in the efficiency of the diagnosis was observed by the combined method. These results suggested that one step RT-PCR combined with nested PCR could be a sensitive, specific, and practical method for diagnosis of CDV infection.

Differential effects of fumonisin B1 on cell death in cultured cells: the significance of the elevated sphinganine

Fumonisins are specific inhibitors of ceramide synthase in sphingolipid metabolism. An alteration in sphingolipid metabolism as a result of fumonisin exposure is related to cell death (Yoo et al., 1992). The objective of this study was to investigate whether elevated free sphinganine levels are related to the sensitivity of cultured cells to fumonisin exposure. Fumonisin B1 elevated the intracellular free sphinganine concentraions in both LLC-PK1 and Chinese hamster ovary (CHO) cells. However, CHO cells are resistant to fumonisin cytotoxicity at 50 microM, while LLC-PK1 cells are sensitive at concentrations greater than 35 microM. The intracellular concentration of free sphinganine in LLC-PK, cells treated at 50 microM fumonisin B1 for 72 h was approximately 1450 pmol/mg protein relative to the 37 pmol observed in the control culture. Under the same conditions, the population of apoptotic cells in the 50 M fumonisin B1-treated culture was approximately 37% of the total compared to 12% in the control. The caspase III-like activity after 72 h in the 50 microM fumonisin B1-exposed culture increased to approximately 50 pmol/mg protein/hr compared to 6 pmol/mg protein/hr in the control. L-cycloserine, a serine palmitoyltransferase inhibitor, reduced the fumonisin B1-stimulated caspase III-like activity down to the control level. Under the same culture conditions, the intracellular concentration of free sphinganine after L-cycloserine plus fumonisin B1 treatment was 140 pmol/mg protein compared to 1450 pmol/mg protein in fumonisin B1 alone. The intracellular concentration of free sphinganine in CHO cells treated with 50 microM fumonisin B1 for 72 h was approximately 460 pmol/mg protein, indicating that the mass amount of elevated free sphinganine in the CHO cells was about 32% of that in LLC-PK1 cells. Adding exogenous sphinganine to the CHO cells along with 50 microM fumonisin B1 treatment for 72 h caused both necrosis and apoptosis. In conclusion, the elevated endogenous sphinganine acts as a contributing factor to the fumonisin-induced cell death.

Rkp1/Cpc2, a fission yeast RACK1 homolog, is involved in actin cytoskeleton organization through protein kinase C, Pck2, signaling

The Rkp1/Cpc2, a fission yeast RACK1 homolog, interacted with Pck2, one of the known PKC homologs, in vivo and in vitro. The rkp1-deletion mutants (Deltarkp1) are elongated and the pck2-deletion mutant (Deltapck2) showed abnormal morphology. The double-deletion mutant (Deltarkp1Deltapck2) showed more aberrant cell shapes and was sensitive to high salt concentration. Both Deltarkp1 and Deltapck2 cells were sensitive to latrunculin B (Lat B) which inhibits actin polymerization. The cells expressing the human RACK1 homolog complemented the latrunculin B sensitivity of Deltarkp1 indicating that human RACK1 is a functional homolog of Rkp1/Cpc2. We propose that Rkp1/Cpc2 may function as a receptor for Pck2 in the regulation of actin cytoskeleton organization during cell wall synthesis and morphogenesis of Schizosaccharomyces pombe.

Radionuclide cisternography in spontaneous intracranial hypotension with simultaneous leaks at the cervicothoracic and lumbar levels

This case report clearly illustrates defined simultaneous cerebrospinal fluid leaks at the cervicothoracic and upper lumbar areas. A 53-year-old woman without a remarkable medical history was hospitalized for sudden onset of severe headache. The headache lasted more than 1 week and standing or sitting positions exaggerated the symptoms, although it was relieved when the patient was recumbent. Radionuclide cisternography was performed using 150 MBq (4 mCi) Tc-99m DTPA. It revealed two cerebrospinal fluid leaks from the cervicothoracic junction bilaterally and the left side of the upper lumbar area. Epidural blood patching was tried at the lumbar level (L1-L2) and showed only a transient effect. A second trial of this method at the level of C7-T1 performed 2 days later resulted in immediate improvement of the symptoms without recurrence. The simultaneous cerebrospinal fluid leaks were detected successfully with radionuclide cisternography using Tc-99m DTPA, which provided a useful guideline for treatment despite the limitations of delayed scanning.

Protein-fatty acid complex for enhanced loading and stability within biodegradable nanoparticles

Lysozyme was hydrophobically modified with a fatty acid, sodium oleate, via an ion-pairing mechanism. Ionic binding between an anionic carboxylic group of sodium oleate and basic amino groups in lysozyme was primarily utilized to form lysozyme-oleate complex. The complex formation was pH dependent. The lysozyme-oleate complex dissolved in an organic solvent exhibited much higher conformational stability at elevated temperature compared with free lysozyme in the same solvent. The complex was formulated into biodegradable nanoparticles by a spontaneous emulsion and solvent diffusion method. The resultant formulation showed near 100% encapsulation efficiency of lysozyme within nanoparticles with < 100 nm in diameter with a narrow size distribution. Lysozyme could be loaded into the nanoparticles up to 18.6% (w/w) with concomitantly increased particle sizes. This study demonstrates a new formulation method of biodegradable nanoparticles with highly efficient encapsulation of proteins, which are potentially useful for oral protein delivery including mucosal vaccination.

Biodegradable polymeric micelles composed of doxorubicin conjugated PLGA-PEG block copolymer

Biodegradable polymeric micelles containing doxorubicin in the core region were prepared from a di-block copolymer composed of doxorubicin-conjugated poly(DL-lactic-co-glycolic acid) (PLGA) and polyethyleneglycol (PEG). The di-block copolymer of PLGA-PEG was first synthesized and the primary amino group of doxorubicin was then conjugated to the terminal hydroxyl group of PLGA, which had been pre-activated using p-nitrophenyl chloroformate. The resulting polymeric micelles in aqueous solution were characterized by measurement of size, drug loading, and critical micelle concentration. The micelles containing chemically-conjugated doxorubicin exhibited a more sustained release profile than PEG-PLGA micelles containing physically-entrapped doxorubicin. The cytotoxic activity of the micelles against HepG2 cells was greater than free doxorubicin, suggesting that the micelles containing conjugated doxorubicin were more effectively taken up cellularly, by an endocytosis mechanism rather than by passive diffusion. Confocal microscopic observation and flow cytometry analysis supported the enhanced cellular uptake of the micelles.

Effect of enrofloxacin-Na against pathogens related to the respiratory and alimentary diseases in suckling and weanling piglets

A field trial was conducted to evaluate effect of enrofloxacin-Na against pathogens related to the respiratory and alimentary diseases in eighty suckling piglets (6-7 days old) and eighty weanling piglets (5-6 weeks old). Respective twenty of the suckling and weanling piglets were assigned to each of 4 experimental groups; control (non-treated), clinical injection dose (CID), 2x clinical injection dose (2CID). and premix. A 0.05 ml (2.5 mg) of enrofloxacin-Na injection (5% solution, 1 ml) per kg body weight of piglets as CID was injected intramuscularly for 3 days and the clinical signs were observed for 9 days. The premix (150 ppm) of enrofloxacin-Na was administered with feed for 7 days ad libitum and the clinical signs were observed for 13 days. The enrofloxacin-Na-treated piglets showed a higher increase in body weight and a lower feed per gain than the control piglets. In addition, the treatment of enrofloxacin-Na, regardless of the route of administration, decreased the incidence rate of diarrhea in suckling piglets and respiratory symptoms in weanling piglets. The isolation index of E. coli and Cl. perfringens during the treatment periods was also lowered by the enrofloxacin-Na treatment in both suckling and weanling piglets. The antibiotics was also evaluated as safe locally and whole bodily as treated by injection or feeding. These results indicate that the newly developed antibiotics, enrofloxacin-Na, is very useful for the prevention and therapy of swine diseases in the pig industry.

Nontumorous hepatic arterial-portal venous shunts: MR imaging findings

PURPOSE

To determine the magnetic resonance (MR) imaging findings of small nontumorous hepatic arterial-portal venous (arterioportal) shunts in the liver.

MATERIALS AND METHODS

MR images in 25 patients with 38 small nontumorous arterioportal shunts verified with surgery or follow-up imaging were included in this study. The causes of arterioportal shunts were iatrogenic causes in 11 patients and/or cirrhotic changes in the remaining patients. Nonenhanced T1- and T2-weighted images and multiphase contrast material-enhanced dynamic images were retrospectively reviewed and compared with conventional hepatic arteriograms to determine the MR characteristics related to the focal hemodynamic changes.

RESULTS

On arterial-dominant-phase dynamic MR images, 29 (76%) of the 38 arteriographically suggested nontumorous arterioportal shunts displayed abnormal findings distinguished against the surrounding hepatic parenchyma, including wedge-shaped (n = 14), nodular (n = 9), or irregularly outlined (n = 6) areas of focal contrast enhancement. The signal intensity on nonenhanced T1- and T2-weighted images of the corresponding areas appeared unremarkable except for three wedge-shaped high-signal-intensity areas (three [8%] of 38) on T2-weighted images accompanied by prolonged contrast enhancement. Most (24 [83%] of 29) areas of abnormal signal intensity were located at the periphery of the liver parenchyma.

CONCLUSION

A small nontumorous arterioportal shunt should be considered one of the causes of focal parenchymal hyperperfusion abnormalities on contrast-enhanced dynamic MR images of the liver in the absence of abnormal signal intensity on static MR images.

Evaluation of expression patterns of feline CD28 and CTLA-4 in feline immunodeficiency virus (FIV)-infected and FIV antigen-induced PBMC

It is known that CD28, a positive costimulatory receptor, plays a very important role in inducing the optimal stimulation of T lymphocytes. CTLA-4 (CD152), however, acts as a negative regulator in T lymphocyte activation. The effect of an feline immunodeficiency virus (FIV) infection on the expression of feline CD28 and CTLA-4 was studied with FIV-infected and uninfected peripheral blood mononuclear cells (PBMC) using a competitive PCR assay. The nature of CD28 and CTLA-4 expression was also examined with fresh and antigen-stimulated PBMC. FIV infection induced a lower expression of CD28, but a higher expression of CTLA-4 in the infected PBMC than in the uninfected PBMC. Relatively high levels of CD28 expression were demonstrated in both the fresh and the antigen-stimulated PBMC. The expression level of CTLA-4 in the freshly isolated PBMC was rather low, however, FIV antigen stimulation induced a relatively high expression of CTLA-4 in feline PBMC.

Regulation of phospholipase D2 by H(2)O(2) in PC12 cells

Phospholipase D2 (PLD2) is expressed in brain and inhibited by synuclein, which is involved in Parkinson's and Alzheimer's diseases. However, the activation mechanism of PLD2 in neuronal cells has not been defined clearly. Hydrogen peroxide (H(2)O(2)) plays roles in the neurodegenerative diseases and also acts as a second messenger of various molecules such as nerve growth factor. To study regulation mechanisms of PLD2 by H(2)O(2) in neuronal cells, we have made stable PC12 cell lines expressing PLD2 (PLD2-PC12 cells). H(2)O(2) treatment stimulated PLD activity in PLD2-PC12 cells in a dose- and time-dependent manner. This activation was inhibited by the treatment with protein kinase C (PKC) inhibitors or by depletion of PKCalpha, -delta, and -epsilon. Phorbol ester markedly activated PLD2. Co-treatment with phorbol ester and H(2)O(2) did not show an additive effect. Chelation of extracellular calcium substantially blocked the H(2)O(2)-induced activation of PLD2. A calcium ionophore induced PLD2 activation in a PKC-dependent manner. Protein-tyrosine kinase inhibitors inhibited H(2)O(2)-induced PLD activation slightly. These data indicate that H(2)O(2) can activate PLD2 in PC12 cells and that this activation is largely dependent on PKC and Ca(2+) ions and minimally dependent on tyrosine phosphorylation.

Gene expression profile and identification of differentially expressed transcripts during human intrathymic T-cell development by cDNA sequencing analysis

The development of immature thymocytes to mature T-lymphocytes is a central process for establishing a functional immune system. The gene regulatory events involved in this process are of outstanding interest in understanding the generation of the T-cell repertoire as well as the differentiation of lineage-specific cells, such as CD4(+) helper T-cells or CD8(+) cytotoxic T-lymphocytes. While some essential genes involved in lineage decision and thymocyte differentiation have been already identified, the exact regulatory mechanisms and differential gene expressions are still unknown. The present study was performed to analyze the gene expression profile during T-cell development, in particular, during the differentiation of immature thymocytes into CD4(+) mature T-cells by analyses of expressed sequence tags (ESTs), and to elucidate novel human genes involved in this process. Based on distinct developmental stages, three PCR-based cDNA libraries from immature CD3(-),4(-),8(-) triple-negative, CD4(+),8(+) double-positive, and mature CD4(+),8(-) single-positive thymocytes were constructed. A total of 1477 randomly selected clones were analyzed by automated single-pass sequencing, and the assembly of ESTs resulted in 1027 different species of contig sequences. Among them, 392 contig sequences were matched to known genes, and several novel transcripts were discovered. The matched clones were classified into seven categories according to their functional aspects, and the gene expression profiles of the three thymocyte subsets were compared. The information obtained in current study will serve as a valuable resource for elucidating the molecular mechanism of intrathymic T-cell development.

Abdominal tuberculous lymphadenopathy: MR imaging findings

BACKGROUND

The purpose of this study was to evaluate the utility of magnetic resonance imaging (MRI) as a diagnostic tool in abdominal tuberculous lymphadenopathy.

METHODS

MRI studies of 11 patients with histologically proven abdominal tuberculous lymphadenopathy were reviewed with regard to anatomic distribution, size, shape, degree, and pattern of enhancement and relation of the lesions to adjacent structures.

RESULTS

The most common site of involvement was the periportal area (n = 6), followed by the peripancreatic (n = 5), mesenteric (n = 1), and paraaortic (n = 1) areas. Eight patients were readily diagnosed as having tuberculous lymphadenopathy on abdominal computed tomography. Three patients had a heterogeneously enhancing masslike lesion adjacent to the pancreas and were initially diagnosed as having cystic tumor of the pancreas. On MRI, 11 lesions showed T1 iso- or hypointensity and central T2 hyperintensity. Two lesions showed T1 iso- or hypointensity and central T2 hypointensity. The lesions with different T2 signal intensities showed different patterns of enhancement on contrast-enhanced dynamic studies. The relations between the enlarged lymph nodes and adjacent bile ducts or vascular structures were well depicted on MRI.

CONCLUSION

MRI was useful in differentiating enlarged lymph nodes abutting the pancreas initially diagnosed as cystic neoplasms on abdominal computed tomography.

Antithrombotic and antiplatelet activities of 2-chloro-3-[4-(ethylcarboxy)-phenyl]-amino-1,4-naphthoquinone (NQ12), a newly synthesized 1,4-naphthoquinone derivative

The possibility of NQ12 (2-chloro-3-[4-(ethylcarboxy)-phenyl]-amino-1,4-naphthoquinone) as a novel antithrombotic agent and its mode of action were investigated. The effects of NQ12 on platelet aggregation in human platelet-rich plasma in vitro, in rats ex vivo, and on murine pulmonary thrombosis in vivo, as well as the mode of antithrombotic action were examined. NQ12 potently inhibited ADP-, collagen-, epinephrine-, and calcium ionophore-induced human platelet aggregations in vitro concentration-dependently. NQ12 significantly inhibited rat platelet aggregation in an ex vivo study. NQ12 prevented murine pulmonary thrombosis in a dose-dependent manner. However, NQ12 did not affect coagulation parameters such as activated partial thromboplastin time, prothrombin time, and thrombin time. NQ12 inhibited fibrinogen binding to the platelet surface GPIIb/IIIa receptor, but failed to inhibit binding to the purified GPIIb/IIIa receptor. Thromboxane B(2) formation caused by thrombin or collagen was inhibited significantly by NQ12. The phosphoinositide breakdown induced by thrombin or collagen was inhibited concentration-dependently by NQ12. These results suggest that NQ12 may be a promising antithrombotic agent, and its antithrombotic activity may be due to antiplatelet aggregation activity, which may result from the inhibition of phosphoinositide breakdown and thromboxane A(2) formation.

Focal lesions in cirrhotic liver: comparing MR imaging during arterial portography with Gd-enhanced dynamic MR imaging

The purpose of this study was to document the additional value of MR imaging during arterial portography (MRAP) in patients examined with intravenous contrast-enhanced dynamic MR imaging for the assessment of focal lesions in patients with cirrhosis or chronic viral hepatitis. The MR images of 24 patients with 39 hepatocellular carcinomas and 18 benign hepatocellular nodules examined with dynamic MR imaging and MRAP within a 14-day interval were retrospectively reviewed. For 39 hepatocellular carcinomas, MRAP revealed 37 perfusion defects (95%), while dynamic MR imaging demonstrated 35 occurrences of nodular contrast-enhancement (90%) on arterial dominant phases. Among the 11 benign nodules misinterpreted as hepatocellular carcinoma due to their high signal intensities on arterial-dominant phases of dynamic MR imaging, eight (73%) showed intratumoral portal venous perfusion on MRAP and were regarded as benign nodules. As a result of its high sensitivity and its potential ability to enable differentiation of benign and malignant hepatocellular nodules, MRAP can be added to dynamic MR imaging for planning future management in patients with equivocal hepatocellular nodules in the cirrhotic liver.

In vitro and in vivo anti-tumor activities of nanoparticles based on doxorubicin-PLGA conjugates

Doxorubicin was chemically conjugated to a terminal end group of poly(D,L-lactic-co-glycolic acid) [PLGA] by an ester linkage and the doxorubicin-PLGA conjugate was formulated into nanoparticles. A carboxylic acid end group of PLGA was conjugated to a primary hydroxyl group of doxorubicin. The primary amine group of doxorubicin was protected during the conjugation process and then deprotected. The nanoparticles containing the conjugate exhibited sustained doxorubicin release profiles over a 1-month period, whereas those containing unconjugated free doxorubicin showed a rapid doxorubicin release within 5 days. Doxorubicin release patterns could be controlled by conjugating doxorubicin to PLGA having different molecular weights. The conjugated doxorubicin nanoparticles showed increased uptake within a HepG2 cell line, which was quantitated by a flow cytometry and visualized by confocal microscopy. The nanoparticles exhibited slightly lower IC(50) value against the HepG2 cell line compared to that of free doxorubicin. In vivo anti-tumor activity assay also showed that a single injection of the nanoparticles had comparable activity to that of free doxorubicin administered by daily injection. The conjugation approach of doxorubicin to PLGA was potentially useful for the formulation of nanoparticles that requires targeting for cancer cells as well as sustained release at the site.

Cavernous hemangioma arising from the lesser omentum: MR findings

We report the magnetic resonance findings of an unusual hemangioma in the lesser omentum. A well-circumscribed, large mass was identified between the stomach and the left lobe of the liver, with compression of adjacent liver parenchyma. The mass showed low signal intensity (SI) on T1-weighted images, high SI on T2-weighted images with multiple septa, and slightly decreased SI on out-of-phase T1-weighted images. After gadolinium contrast administration, septa within the mass showed minimal enhancement on 30-s T1-weighted images and mild enhancement on 5-min T1-weighted images. The mass was histopathologically diagnosed as a cavernous hemangioma comprised of multiple vascular spaces, fibrotic tissue, and adipocytes.

Failure of neonatal clomipramine treatment to alter forced swim immobility: chronic treadmill or activity-wheel running and imipramine

We examined whether chronic running on a treadmill or activity wheel would attenuate the increased swim immobility that has been reported after neonatal clomipramine (CLI) treatment. Male Sprague-Dawley pups (N = 60) were injected with the monoamine reuptake inhibitor clomipramine hydrochloride (40 mg/kg per day i.p.) from 8 to 21 days of age. Another group (N = 12) received saline vehicle. At age 4 weeks, the CLI pups were randomly assigned to experimental conditions: (1) sedentary; (2) 24-h access to an activity wheel; (3) sedentary that received the antidepressant drug imipramine hydrochloride (10 mg/kg twice daily) during the last 10 days of the experiment; (4) activity wheel + imipramine; (5) treadmill running (30 m/min for 1 h at 0 degrees incline, 6 days/week). At age 16 weeks, rats underwent the Porsolt swim test 48 h after the last imipramine injection and/or the last exercise session. The increase in swim immobility among CLI-treated rats was small (one quarter of SD) and not statistically significant (p>0.10). The results are not consistent with our previous finding of antidepressant-like effects of activity-wheel running based on brain noradrenergic adaptations and enhanced male copulatory performance after neonatal CLI treatment. The lack of change in swim performance after clomipramine questions the generalizability of the CLI model of depression and the validity of the forced swim test as a behavioral measure of depression when it is used after neonatal CLI injection or chronic activity-wheel running.

Detection of genetic alterations in the human gastric cancer cell lines by two-dimensional analysis of genomic DNA

We examined genomic DNA from each of three human-derived gastric cancer cell lines, using the technique of restriction landmark genomic scanning (RLGS) which allows monitoring of approximately 2, 000 NotI landmarks. The resulting DNA spots from cancer cell DNA were compared with those in normal mucosa or gastric primary tumor. In all, 9 intense spots were detected from two of the three cancer cell lines. Two highly intensified spots were common in the two cancer cell lines and proven to be originated from DNA region containing the human c-myc proto-oncogene on chromosome 8. The degree of amplification of c-myc DNA was similar to each other and was estimated to be 60-fold as compared to those from normal mucosa DNA. On the basis of chromosome-assigned RLGS (CA-RLGS), other spots were assigned to each chromosome, such as one on chromosome 8, two each from chromosome 20, and three on one of chromosome 9-12. The remaining spot seems to be due to demethylation of a repetitive element. Twenty-four spot that were lost due to either homozygous deletion or methylation on corresponding NotI cleavage sites were commonly observed in all cancer cells. These spots were also assigned to each chromosome: one each from chromosome 2, 6, 7, 13, 14, 16, and 20, two each from chromosome 3 and 5, and nine from chromosome 9-12 by CA-RLGS. Many of the multi-copy spots corresponding to ribosomal RNA genes were greatly decreased due mainly to methylation on CpG islands along with minor rDNA variants, indicating that only minor rRNA genes may be silenced in these cancer cells. These results show that the present alterations detected by RLGS might be useful for identification of candidate genes inactivated or expressed unexpectedly in tumor development and tumor progression in the stomach.

Test-bolus injection for optimization of arterial phase imaging during contrast-enhanced hepatic MR imaging

Contrast enhancement during the dynamic MR imaging is important for the detection and characterization of focal liver lesions. The purpose of this study was to determine whether or not a timing examination with a injection of a 1.0-mL bolus of gadopentetate dimeglumine into the antecubital vein followed by rapid dynamic scanning and measurement of signal intensity of the aorta could help to obtain proper arterial-dominant phase images for the characterization of focal hepatic lesions during subsequent multiphase dynamic MR imaging. The imaging delay to acquisition of the first gadolinium-enhanced image for multiphase dynamic MR imaging was set to equal the time to peak aortic enhancement during the test examination. The first contrast-enhanced images of 80 patients with 160 focal liver lesions (hepatocellular carcinoma, n = 79; cavernous hemangioma, n = 51; metastatic tumor, n = 30) were then retrospectively reviewed. Peak aortic enhancement occurred between 10 and 28 seconds (mean, 16.5 seconds +/- 3.1) after starting the infusion of contrast material in 80 patients during the test-examination. Depending on the findings of intrahepatic vascular enhancement on the full-scale dynamic images, hepatic arterial phase (n = 11, 14%) or sinusoid phase (n = 65, 81%) imaging was obtained during the first gadolinium-enhanced acquisition in 76 (95%) of 80 patients. Three different lesions were well characterized and easily distinguished from each other (p < .0001) on the first-phase images depending on their enhancement pattern. In the majority of patients, timing examination with test-bolus injection was helpful in obtaining qualified images for the characterization of various focal lesions.

Phenotypic and functional analysis of bovine gammadelta lymphocytes

The studies have provided the first comprehensive comparison of the factors regulating activation and proliferation of WC1+ and WC1- gammadelta T cells. The investigation has shown that accessory molecules essential for activation and function of WC1+ and WC1- gammadelta T cells and the sources and roles of cytokines in activation of gammadelta T cells through the T cell receptor (TCR). The study has also shown that the role of cytokines in activation and function of gammadelta T cells activated indirectly through cytokines secreted by ab T cells, accessory cells and antigen presenting cells (APC). Cytokines were differentially produced by subpopulations of gammadelta T cells under different conditions of activation. The investigation obtained in this study has revealed that factors account for activation and proliferation of gammadelta T cells in cultures designed to study MHC-restricted responses to antigens. Evidence obtained here has shown there is biological relevance to activation under these culture conditions that points to potential regulatory and effector functions of gammadelta T cells. The investigations have also provided the information needed to begin identifying and characterizing antigens recognized by the TCR repertoires of WC1+ and WC1- gammadelta T cells. Finally, the investigations have provided the information needed to begin analysis of the mechanisms by which gammadelta T cells modulate MHC restricted immune responses to pathogens and derived vaccines.