Modulation of gelatinase activity correlates with the dedifferentiation profile of regenerating salamander limbs

Remodeling of extracellular matrix (ECM) is one of the key events in many developmental processes. In the present study, a temporal profile of gelatinase activities in regenerating salamander limbs was examined zymographically. In addition, the effect of retinoic acid (RA) on these enzyme activities was examined to relate the pattern-duplicating effect of RA in limb regenerates with gelatinase activities. During regeneration, various types of gelatinase activities were detected, and these activities were at their maximum levels at the dedifferentiation stage. Upon treatment with chelating agents EDTA and 1,10-phenanthroline, the enzyme activities were inhibited indicating that those enzymes are likely matrix metalloproteinases (MMPs). Considering the molecular sizes and the decrease of molecular sizes by treatment with p-aminophenylmercuric acetate, an artificial activator of proMMP, some of the gelatinases expressed during limb regeneration are presumed to be MMP-2 and MMP-9. In RA-treated regenerates, overall gelatinase activities increased, especially the MMP-2-like gelatinase activity which increased markedly. These results suggest that MMP-2-like and MMP-9-like gelatinases play a role in ECM remodeling during regeneration, and that gelatinases are involved in the excessive dedifferentiation after RA treatment.

Differentiation of small hyperechoic renal cell carcinoma from angiomyolipoma: computer-aided tissue echo quantification

To assess the value of computer-aided tissue echo quantification in differentiating small hyperechoic renal cell carcinomas from angiomyolipomas, we studied ultrasonographic images of 15 renal cell carcinomas and 20 angiomyolipomas. After digitizing the images, we measured the absolute gray scale values of the renal cortex, central echo complex, and mass. The relative gray scale value (%) of the mass was calculated by setting the gray scale value of the cortex as 0% and the central echo complex as 100%. The relative gray scale value of renal cell carcinomas was in the range of 12 to 73% (mean, 28%), whereas that of angiomyolipomas was 30 to 204% (mean, 130%). The differentiation between small hyperechoic renal cell carcinomas and angiomyolipomas can be facilitated by computer-aided tissue echo quantification.

Erwinia pyrifoliae sp. nov., a novel pathogen that affects Asian pear trees (Pyrus pyrifolia Nakai)

A novel pathogen from Asian pears (Pyrus pyrifolia Nakai) was analysed by sequencing the 16S rDNA and the adjacent intergenic region, and the data were compared to related Enterobacteriaceae. The 16S rDNA of the Asian pear pathogen was almost identical with the sequence of Erwinia amylovora, in contrast to the 16S-23S rRNA intergenic transcribed spacer region of both species. A dendrogram was deduced from determined sequences of the spacer regions including those of several related species such as Erwinia amylovora, Enterobacter pyrinus, Pantoea stewartii subsp. stewartii and Escherichia coli. Dendrograms derived from 121 biochemical characteristics including Biotype 100 data placed the Asian pear pathogen close to Erwinia amylovora and more distantly to other members of the species Erwinia and to the species Pantoea and Enterobacter. Another DNA relatedness study was performed by DNA hybridizations and estimation of delta Tm values. The Asian pear strains constituted a tight DNA hybridization group (89-100%) and were barely related to strains of Erwinia amylovora (40-50%) with a delta Tm in the range of 5.2-6.8. The G + C content of DNA from the novel pathogen is 52 mol%. Therefore, it is proposed that strains isolated from Asian pears constitute a new species and the name Erwinia pyrifoliae is suggested; the type strain is strain Ep 16/96T (= CFBP 4172T = DSM 12163T).

Value of ICAM-1 expression and soluble ICAM-1 level as a marker of activity in sarcoidosis

BACKGROUND

The natural course of sarcoidosis is variable, but no single parameter has been generally accepted as a good marker for disease activity. Adhesion molecules are required for the migration of inflammatory cells; thus, they may be markers of activity in sarcoidosis.

METHODS

In 16 patients with active sarcoidosis and 11 with inactive disease (10 were male, 17 were female; mean age [-/+ SD], 39.6+/-11.0 years; mean follow-up, 21+/-16 months), the expression of adhesion molecules on cells obtained with BAL (measured by flow cytometry) and the level of soluble intercellular adhesion molecule 1 (sICAM-1) in the serum and BAL fluid (BALF) were measured at the time of diagnosis and during the follow-up. The changes in serum sICAM-1 level and ICAM-1 expression on cells obtained with BAL were compared with the clinical course of the disease.

RESULTS

In patients with active disease, the ICAM-1 on alveolar macrophage (AM) (relative linear median fluorescence intensity [RMFI], 3.21+/-1.55) and sICAM-1 levels in serum (575+/-221 ng/mL) and BALF (47.3+/-19.3 ng/mL) were higher than those for patients with inactive disease (RMFI, 1.67+/-0.66; p = 0.0034; serum, 263+/-98.5 ng/mL; p = 0.0001; BALF, 27.5+/-19.0 ng/mL; p = 0.0209). In the patients with active disease, ICAMN-1 on AM and serum sICAM-1 decreased (RMFI, 1.51+/-0.84; 284+/-118 ng/mL, respectively) after steroid therapy, but no significant change was noted in patients with inactive disease. We also found that the initial ICAM-1 on AM and serum sICAM-1 had a significant correlation with the degree of improvement in pulmonary function tests after the therapy. The disease relapsed in four patients after the discontinuation of steroids, and the serum sICAM-1 level was elevated again at the time of relapse.

CONCLUSION

Our data suggest that the serum sICAM-1 level and the ICAM-1 expression on AM may be good markers of disease activity and also a predictor of outcome in sarcoidosis.

Complicated pleural tuberculosis in children: CT evaluation

PURPOSE

To describe the CT features of complicated pleural tuberculosis in children and to define the use of CT in children with pleural tuberculosis.

MATERIALS AND METHODS

The CT findings in 11 children with complicated pleural tuberculosis were retrospectively analysed. CT was performed to evaluate persistent pleural thickening (n = 6) or a mass-like lesion (n = 5) detected on plain radiographs. Chest radiographs and medical records were reviewed to determine whether additional information provided by CT had altered clinical management.

RESULTS

On CT, more than one location was involved in five patients (45%) and in two patients (18%) the entire pleural spaces were involved. Pleural thickening was seen in all 11 patients and enhancement after administration of contrast medium occurred in ten patients (91%). Low-density fluid collections were seen in nine patients (82%) and in two, CT revealed fluid collections within calcified pleural lesions. In five patients with mass-like lesions on plain radiographs, CT showed a low-density pleural mass with peripheral enhancement in four and a calcified pleural mass with fluid collection in one. CT demonstrated parenchymal abnormalities on the same side as pleural lesions in all 11 patients and hilar or mediastinal adenopathy in four. Four patients (36%) underwent surgery because of fluid within a calcified fibrothorax (n = 3) and chest wall tuberculosis (n = 1) that were seen only on CT.

CONCLUSIONS

The CT features of complicated pleural tuberculosis in children were pleural thickening, enhancement and fluid collection with associated parenchymal abnormalities and lymphadenopathy. In the evaluation of children with pleural tuberculosis, CT can be useful for demonstrating fluid within a calcified fibrothorax or chest wall involvement, which usually requires surgical intervention.

Change in corneal sensitivity following laser in situ keratomileusis

PURPOSE

To evaluate the change in corneal sensitivity following laser in situ keratomileusis (LASIK).

SETTING

Department of Ophthalmology, Maryknoll Hospital, Pusan, Korea.

METHODS

The corneal sensitivity in 40 eyes (32 patients) was measured before and 1 and 2 weeks and 1, 3, and 6 months after LASIK. Sensitivity measurements were made with an esthesiometer at central, temporal, inferior, nasal, and superior points on the corneal flap. The eyes were grouped by ablation depth: Group 1, corneal ablation depth less than 100 microns; Group 2, corneal ablation depth more than 100 microns.

RESULTS

Corneal sensitivity did not recover to the preoperative level by 6 months after LASIK. Except at the hinge of the corneal flap, the pattern of sensitivity recovery was similar among the various points. Recovery was more rapid at the hinge than at other areas (P < .05). There was a trend toward a greater reduction in corneal sensitivity in Group 2, the group with deeper ablations, than in Group 1.

CONCLUSION

The results suggest that lamellar cutting of the cornea during LASIK impairs corneal sensitivity and that the depth of the corneal ablation affects the extent of corneal sensitivity loss and recovery.

Differentiation of Lactococcus lactis subspecies lactis and subspecies cremoris strains by their adaptive response to stresses

Lactococcus lactis subspecies lactis (L. lactis ssp. lactis) and Lactococcus lactis subspecies cremoris (L. lactis ssp. cremoris) were investigated in respect to their response to acid, bile-salt and freezing stresses. First, the sublethal and lethal levels of each stress were determined for both subspecies. For acid stress, the levels were pH 4.5 and 2.5, respectively, for L. lactis ssp. lactis, and pH 5.0 and 3.0, respectively, for L. lactis ssp. cremoris. For bile-salt stress, the levels were 0.03 and 0.1%, respectively, for L. lactis ssp. lactis, and 0.01 and 0.04%, respectively, for L. lactis ssp. cremoris. For freezing stress, 10 degrees C was used as the sublethal temperature and -20 degrees C was used as the lethal temperature for both subspecies. To evaluate the effect of each stress at log phase, a log-phase culture was challenged directly with the appropriate lethal level (control culture) and a second log-phase culture was pre-exposed to the appropriate sublethal level prior to testing survival under normally lethal conditions (test culture). Some, if not most, of the cells were killed in the control cultures for all three stresses. However, in the test cultures, the viability was significantly improved for all of the L. lactis ssp. lactis strains tested, but not for the L. lactis ssp. cremoris strains. It appears, therefore, that L. lactis ssp. lactis is capable of displaying adaptive response to stresses, whereas L. lactis ssp. cremoris seems to lack this phenotype or the response is much weaker in this subspecies. The effect of each stress on stationary-phase cultures was also investigated. Unlike the log-phase cultures, the stationary-phase cultures of both subspecies, challenged directly with the lethal levels, were highly resistant to each of the three stresses tested.

Properties of coralline hydroxyapatite and expanded polytetrafluoroethylene membrane in the immature craniofacial skeleton

Although extensive research regarding the treatment of calvarial defects has been done in adult models, little is known about the response in the maturing skeleton. The role of coralline hydroxyapatite and expanded polytetrafluoroethylene membrane in augmenting bone growth and repair of calvarial defects in a neonatal model is explored. Utilizing a 3-week-old neonatal swine model, bone growth into 28 calvarial defects was measured. After exposure of the calvaria in seven animals, four defects of 10 mm in diameter were created. In each animal, one defect was treated with a 10-mm disc of porous hydroxyapatite alone (Interpore 500, Interpore International), and a second defect was covered with an expanded polytetrafluoroethylene membrane (Gore-Tex OV-6) secured by four 3-mm microscrews (Luhr Microsystem, Howe-Medica Inc.). The third defect combined an implanted hydroxyapatite disc covered by an expanded polytetrafluoroethylene membrane, whereas the fourth defect served as an untreated control. Histology and histomorphometry were performed on undecalcified specimens harvested at 6 weeks after surgery. In both hydroxyapatite groups, the bone growth into the inorganic matrix provided complete osseous union in all specimens, and the amount of fibrosis was significantly lower (p < 0.02) in comparison with the control. Unexpectedly, there was significant osteoclastic resorption of the hydroxyapatite matrix (35.1 percent decrease) with simultaneous bone deposition and remodeling. The addition of an expanded polytetrafluoroethylene membrane covering the hydroxyapatite implant provided an insignificant advantage in bone growth (27.3 percent versus 28.3 percent, respectively). Finally, the expanded polytetrafluoroethylene membrane alone afforded no qualitative advantage secondary to intrusion of brain and dura into the defect as well as displacement of the membrane inward during appositional growth, leading to incomplete healing of the defect with thinning of the surrounding cranial bone. Unique in this maturing model was morphologic evidence of complete union at the calvaria-hydroxyapatite interface in all specimens as well as active remodeling of the hydroxyapatite matrix. The results of this study suggest that porous hydroxyapatite may be a suitable bone substitute in maturing calvarial bone defects, achieving superior osseous integration and volumetric bone gain while undergoing concurrent resorption and remodeling.

Reduced transforming growth factor-beta type II receptor (TGF-beta RII) expression in adenocarcinoma of the lung

BACKGROUND

TGF-beta type II receptor is considered as one of the tumor suppressor genes, and altered expression of TGF-beta RII has been found in many kinds of cancers.

MATERIALS AND METHODS

Seven NSCLC cell lines and 21 surgically resected NSCLC tissues were obtained. The growth inhibition by TGF-beta 1 was examined by MTT assay. Northern blot and Southern blot analysis were performed for TGF-beta 1 and TGF-beta RII in NSCLC cell lines. TGF-beta 1 and TGF-beta RII expression were analyzed by immunohistochemistry (IHC) in 21 surgically resected NSCLC tissues.

RESULTS

Six of 7 NSCLC cell lines were resistant to TGF-beta 1. Southern blot analysis for TGF-beta 1 and TGF-beta RII showed no genetic changes. However, mRNAs of TGF-beta RII were barely detectable in 3 of 7 cell lines, and mRNAs of TGF-beta 1 were almost undetectable in 2 of 7. IHC revealed decreased TGF-beta RII expression in 6 of 21 surgically resected NSCLC tissues (5 adenocarcinomas, 1 sarcomatoid carcinoma). Being analyzed by the histologic subtypes, TGF-beta RII decreased in 5 of 8 adenocarcinomas but in only 1 of 13 non-adenocarcinomas (p = 0.0139). On the other hand, TGF-beta 1 was expressed at a higher level in 20 of 21 tumors.

CONCLUSION

These results suggest that decreased TGF-beta RII expression may play a role in human lung carcinogenesis, especially in adenocarcinoma.

Respiratory and haemodynamic effects of the prone position at two different levels of PEEP in a canine acute lung injury model

This study was designed to examine whether the oxygenation response in the prone position differs in magnitude depending on the level of positive end-expiratory pressure (PEEP) applied in the supine position, and whether cardiac output (CO) increases in the prone position. In seven supine dogs, acute lung injury was established by saline lavage (arterial oxygen tension (Pa,O2)/inspiratory oxygen fraction (FI,O2) 17.8+/-9.6 kPa (134+/-72 mmHg)), and inflection point (Pflex) of the respiratory system was measured (6.6+/-1.4 cmH2O). Pa,O2/FI,O2 and CO of the supine and prone positions were obtained under the application of low PEEP and then under optimal PEEP (2 cmH2O below and above Pflex, respectively). The net increase in Pa,O2/FI,O2 by prone positioning was greater at low PEEP (27.3+/-12.0 kPa (205+/-90 mmHg)) than at optimal PEEP (4.4+/-13.0 kPa (33+/-98 mmHg)) (p=0.006). CO decreased significantly with optimal PEEP in the supine position (2.4+/-0.5 versus 3.1+/-0.4 L x min(-1) at baseline, p<0.001), and increased to 3.4+/-0.6 and 3.6+/-0.7 L x min(-1) in the prone position at 5 min and 30 min, respectively (both p=0.018). When the dogs were turned supine at optimal PEEP, CO again decreased (2.4+/-0.5 L x min(-1), p<0.001). In conclusion, the prone position augmented the effect of relatively low positive end-expiratory pressure on oxygenation, and attenuated the haemodynamic impairment of relatively high positive end-expiratory pressure in a canine acute lung injury model.

Molecular cloning of capillary permeability-increasing enzyme-2 from Agkistrodon caliginosus (Korean viper)

The gene of capillary permeability-increasing enzyme-2 (CPI enzyme-2) was cloned from the cDNA library of Agkistrodon caliginosus and its nucleotide sequence was determined. Its sequence indicates that CPI enzyme-2 is synthesized as a pre-zymogen of 258 amino acid residues, including a putative secretory signal peptide of 18 amino acids and a proposed zymogen peptide of 6 amino acids. The amino terminal sequence deduced from the cDNA sequence was exactly consistent with that of CPI enzyme-2 except for the substitution of an amino acid (Gly27-->Ser). The open reading frame is very similar to those of plasminogen activator and thrombin-like proteases cloned from other snakes. The clone encoding CPI enzyme-2 belongs to the serine protease family. The active site of the enzyme is highly conserved at His41, Asp86 and Ser180. Its possible glycosylation sites, Asn-X-Thr/Ser, are located at amino acid residues 20-22, 55-57, 79-81 and 97-99.

Conservation of the major cold shock protein in lactic acid bacteria

Primers designed from consensus regions of the major cold shock gene of different bacterial species were used in PCR amplification of Lactic Acid Bacteria (LAB). An appropriately-sized PCR product was obtained from Lactococcus lactis subsp. lactis LL43-1 and MG1363; Lactococcus lactis subsp. cremoris LC10-1, LC11-1, and LC12-1; Streptococcus thermophilus ST1-1; Enterococcus faecalis EF1-1; Lactobacillus acidophilus LA1-1; Lactobacillus helveticus LH1-1; Pediococcus pentosaceus PP1-1; and Bifidobacterium animalis BA1-1. The PCR products were cloned and sequenced. The deduced amino acid sequences displayed high sequence similarity with the major cold shock proteins of Escherichia coli and Bacillus subtilis and the human Y-box factor. The amino acid residues of the cold shock domain implicated in nucleic acid binding in several unrelated species were also highly conserved in the LAB strains. It is possible, therefore, that this protein in LAB may also act as a transcriptional enhancer to other cold shock genes and/or act as an RNA chaperone unwinding tightly folded RNA molecules.

Choledochal cyst with or without biliary atresia in neonates and young infants: US differentiation

PURPOSE

To differentiate at ultrasonography (US) between the choledochal cyst associated with biliary atresia (CCBA) and that in the absence of biliary atresia (CC) in neonates and young infants.

MATERIALS AND METHODS

Preoperative US findings in 28 neonates and infants younger than 4 months in whom choledochal cyst was subsequently surgically confirmed were retrospectively analyzed. There was no statistically significant difference in age between the CCBA group (n = 19) and the CC group (n = 9). US findings in both groups were compared, with focus on the size of the cyst in the hepatic portal, dilatation of the intrahepatic bile ducts, and the size and morphology of the gallbladder.

RESULTS

At US, the width and length of the cysts in the hepatic portal in the CC group were significantly larger than those in the CCBA group (P < .001). Dilatation of the intrahepatic bile ducts, seen in only one patient (5%) of the CCBA group, was observed in all patients (100%) of the CC group. The gallbladder was normal or distended in all patients of the CC group, while it was atretic or irregularly elongated in 17 patients (89%) of the CCBA group.

CONCLUSION

US can be helpful in the preoperative differential diagnosis of choledochal cysts in neonates and infants. Cysts are larger, intrahepatic ducts are dilated, and gallbladders are not atretic in patients with CC as compared with those in patients with CCBA.

Continuous separation of serum proteins using a stirred cell charged with carboxylated and sulfonated microspheres

We contrived a new separation system using a stirred cell charged with uncoupled microsphere similar to the chromatographic separation. Microspheres, carboxylated PS/PMAA and sulfonated PS/PNaSS, were prepared by emulsifier-free emulsion polymerization. To complement the submicron size weakness and the absence of ligands, we employed the latex form, the dispersion of microsphere, and took advantage of interaction relationships between proteins and microspheres. Adsorption isotherm is contemplated to investigate continuous separation behaviours of serum proteins. Selectivity of separation is in the following order: PS/PNaSS-2.0 (high sulfonated) < PS/PNaSS-0.3 (low sulfonated) < PS/PMAA-0.5 (low carboxylated). Unlike previous works on batch separation, not only the adsorbed amount in equilibrium (Cm), but also adsorption coefficient (K), played an important role in continuous separation. Functional groups (carboxyl and sulfonate), induced from the co-monomer, also affected the adsorption behaviours.

Radiological features of focal nodular hyperplasia of the liver in children

BACKGROUND

Focal nodular hyperplasia (FNH) is an unusual hepatic tumour in children and should be distinguished from other hepatic lesions.

OBJECTIVE

To describe the imaging characteristics of FNH in children.

MATERIALS AND METHODS

We examined five patients (three boys and two girls, mean age 9.4 years) with pathologically confirmed FNH. The diagnosis was obtained by tumour resection (n = 4) and percutaneous needle biopsy (n = 1). One patient with multiple FNHs showed recurrent lesions after tumour resection. All patients were studied with US (including colour and power Doppler US [n = 3]) and CT. Dynamic enhanced CT scans were available in three patients. MRI (n = 2) or coeliac angiography (n = 1) was performed in three patients.

RESULTS

Seven of eight FNH lesions in five patients were demonstrated by imaging. The average size of the lesions was 6.5 cm. Six lesions detected on US showed variable echogenicity with a central hyperechoic scar (n = 2). On Doppler examination, central or peripheral hypervascular areas were seen (n = 3). Six lesions detected on contrast-enhanced CT showed high attenuation (n = 4) or iso-attenuation (n = 2). On early phase scans, all the lesions (n = 3) showed high attenuation. Irregular linear or ovoid central scars were detected in two patients on CT. MR demonstrated three lesions in two patients, one of which had not been detected by US or CT. A central low signal intensity scar (n = 1) was seen on T2-weighted MRI. Coeliac angiography performed in one patient showed a hypervascular mass with homogeneous staining.

CONCLUSION

FNH in children shows a wide spectrum of imaging findings on various radiological examinations and the typical central scar was not always seen on imaging studies. Dynamic enhanced CT obtained in the early phase and colour Doppler studies may be helpful in the diagnosis of FNH by allowing characterisation of tumour vascularity. FNH should be included in the differential diagnosis of liver mass in children.

Degradation of acharan sulfate and heparin by Bacteroides stercoris HJ-15, a human intestinal bacterium

When glycosaminoglycan (GAG)-degrading enzymes were measured in normal human stool suspensions, all 5 tested different stools degraded titrable heparin and acharan sulfate. GAG-degrading bacteria were screened from the isolates of human stools. Among them, HJ-15 had the most potent activities of heparinases (GAGs-degrading enzymes). However, HJ-15 produced the enzyme even if in the media without heparin. Acharan sulfate lyase was induced by acharan sulfate and heparin. Heparinase production was also induced by these GAGs. These enzymes, acharan sulfate lyase and heparinase, were produced in exponential and stationary phase of HJ-15 growth, respectively. Optimal pHs of the acharan sulfate lyase and heparinase activities were 7.2 and 7.5, respectively. The biochemical properties of HJ-15 was similar to those of B. stercoris. However, difference from B. stercoris was utilization of raffinose. This HJ-15 also degraded chondroitin sulfates A and C.

Locoregional response and increased natural killer activity after intratumoral injection of HLA-B7/beta2-microglobulin gene in patients with cancer

The purpose of this study was to assess the therapeutic potential of injecting the gene for HLA-B7/beta2-microglobulin into the subcutaneous metastatic nodules of patients who are refractory to conventional treatments. The nine patients evaluated were divided into three groups and given escalating doses of DNA (20, 40, and 100 microg of the HLA-B7 plasmid DNA/lipid complex for each group) every 2 weeks. Biopsy specimens from the treated tumor nodules of all nine patients were positive for the presence of DNA and for HLA-B7 mRNA expression. Moreover, in six of the nine patients, immunohistology of tumor biopsy samples revealed the expression of recombinant HLA-B7 protein. Also, all nine patients showed an increase in NK activity in their circulating peripheral blood lymphocytes. In two lung cancer patients, one partial and one mixed response was observed after gene transfer. These responses were confined to the treated nodules and the untreated locoregional lymph nodes; the lung masses showed no regression. Remission durations were 14 and 6 weeks, respectively, and in a total of 35 cycles no significant toxicities were observed. Immunohistologic analysis revealed an increased infiltration of CD4+ T cells, macrophages, and NK cells after therapy. In two responding cases, direct intratumoral injection of an allogeneic class I gene could elicit an antitumor response in locoregional areas, possibly through the activation of NK cells.

Effect of cold shock on protein synthesis and on cryotolerance of cells frozen for long periods in Lactococcus lactis

Aspects of the cold-shock response in Lactococcus lactis subsp. lactis LL41-1 were investigated. First, it was determined whether new proteins were synthesized in response to cold shock. Cell-free extracts were prepared from a cold-shocked (exposed to 10 degreesC for 5 h) culture (cfe-cs) and from a non-cold-shocked (held at 30 degreesC continuously) culture (cfe-non), and were subjected to sodium dodecyl sulphate-polyacrylamide gel electrophoresis. A protein of approximately 6.3 kDa was present in the cfe-cs and appeared not to be present in the cfe-non. No other changes were evident. Second, the effect of cold shock on cryotolerance of cells that have been frozen at -20 degreesC for up to 1 year was examined. Without the cold-shock treatment prior to freezing the cell viability following freezing for 1 day was 34%, 14 days 32%, 182 days 7%, and 364 days 0.2%. However, with the cold shock treatment it was 83%, 82%, 12%, and 0.8%, respectively. It appears that cold shock significantly improves cryotolerance of the cells for short periods of freezing, but the protective effect was less marked following longer storage periods.

Upregulation of cathepsin D expression in the dedifferentiating salamander limb regenerates and enhancement of its expression by retinoic acid

In the regenerating urodele limb, catheptic activity has been known to be present in the stump tissue undergoing histolysis, and it has been implicated in the modification of some intracellular and extracellular matrix molecules. In this study, we compared spatial and temporal gene expression profiles of cathepsin D in normal, retinoic acid-treated, or denervated larval limb regenerates of Hynobius leechii and compared cathepsin D activities between normal and retinoic acid-treated limb regenerates. The results showed that the expression of cathepsin D increased markedly in the vicinity of an amputation site under the wound epidermis at dedifferentiation stage, whereas the expression level of cathepsin D was low in the denervated limb. With retinoic acid treatment, the expression of cathepsin D was elevated in terms of both level and duration. In addition, the profile of cathepsin D activity coincided well with the expression profile of cathepsin D in normal and retinoic acid-treated limb regenerates. These results suggest that the increase of cathepsin D activity during the dedifferentiation period is due to the upregulation of cathepsin D transcription, and nerve factors are involved in this process. Furthermore, retinoic acid appears to upregulate cathepsin D expression, which might be linked to the enhanced dedifferentiation in the retinoic acid-treated limb regenerates.

Differential effects and transport kinetics of ascorbate derivatives in leukemic cell lines

In order to investigate the differential effects of ascorbate derivatives on leukemic cell growth, we examined their stabilities and transmembrane transport efficiencies. The growth of HL-60 and U937 cells was dose-dependently inhibited by ascorbic acid and sodium ascorbate, but not by dehydroascorbic acid and magnesium ascorbyl 2-phosphate up to 200 microM. The growth-suppression by ascorbic acid was dependent on its redox state, showing a complete or partial reversion by ascorbate oxidase or FeCl3 addition, respectively. Three different patterns of intracellular ascorbic acid accumulation were observed by HPLC according to the species of ascorbate derivative applied for the incubation. Compared with the reduced form of ascorbic acid, the oxidized forms (dehydroascorbic acid, ascorbic acid plus ascorbate oxidase or FeCl3) were rapidly transported into cells and readily degraded, while magnesium ascorbyl 2-phosphate, a stable derivative of ascorbic acid, slowly elevated the intracellular level of ascorbic acid, reaching a plateau at 24 hours. We also measured the differential kinetics of ascorbic acid levels In culture supernatants following the addition of ascorbate derivatives. Ascorbic acid at 40, 10, or 1 microM was observed 3 hours following treatment with 100 microM of ascorbic acid, ascorbic acid plus FeCl3, or magnesium ascorbyl 2-phosphate, respectively. No ascorbic acid was found in the culture supernatant treated with dehydroascorbic acid. This order of ascorbic acid concentrations in culture supernatant reflects their growth-inhibitory effects. Thus the growth inhibitory effect of ascorbic acid appears to be dependent on its concentration in culture medium rather than its intracellular concentration. In conclusion, the results in this study indicate that the differential effects of ascorbate derivatives appear to be due to the actual concentration differences of the reduced form of ascorbic acid in culture medium following their addition, which is determined by their stability and efficiency of cellular uptake.

Natural killer cell activity depression in peripheral blood and ascites from gastric cancer patients with high TGF-beta 1 expression

Transforming growth factor beta 1 (TGF-beta 1) has been shown to inhibit the function of various types of cells in vitro such as natural killer (NK) cells. However, this activity has not been well characterized in vivo. Therefore, twenty three patients with advanced gastric adenocarcinoma (AGC), with cytologically-proven malignant ascites, were evaluated in this study. We determined whether the NK activities of their lymphocytes from either peripheral blood or ascites were suppressed by tumor cell TGF-beta 1 expression. We also examined whether NK activity was more suppressed in peripheral blood versus in ascites where tumor cell-derived TGF-beta 1 is potentially more locally concentrated. The expression of TGF-beta 1 mRNA was examined in the tumor cells from the ascitic fluid of the AGC patients. The NK activities of lymphocytes in peripheral blood and ascites were measured by the 4-hour 51Cr-release assay. We determined that eleven of twenty three patients had tumor cells expressing high levels of TGF-beta 1 mRNA. The NK activity in these eleven patients was significantly lower than the NK activity in peripheral blood and ascites from twelve patients with low TGF-beta 1 expression. In addition, the NK activity in malignant ascites was significantly lower than the activity in peripheral blood in these high TGF-beta 1-expressing cancer patients (p < 0.05). We also monitored survival time in these advanced gastric cancer patients. However, the patients with high expression of TGF-beta 1 showed a trend towards reduced survival although this was not statistically significant. The data in this study are consistent with observations in the previous experiments that showed inhibitory effects of TGF-beta 1 on NK activities in vitro, we reported the same phenomenon in patients with advanced gastric cancer.

A case of hydroa vacciniforme with unusual ear mutilation

A 22 year-old man visited our department with a 18-year-history of recurrent vesicular eruption on his skin when exposed to the sun. History revealed that the skin lesions developed as vesicles at first, then over the next several days, they formed crusts and healed with scarring. We were able to induce skin lesions by a repetitive UV-A provocation test. By the clinical and histologic features of the induced lesions, the case was diagnosed as hydroa vacciniforme (HV). However, no vesicular lesions were found on physical examination. Instead, in addition to varioliform scarring, we found various unusual clinical manifestations: burn-like lesions and crusts, flexion contracture of the digitum, and ear lobe mutilation. The ear lobe mutilation, which had not been reported previously in HV, was especially interesting.

Cloning of genes specifically expressed in rice embryogenic cells

We have examined differences in gene expression pattern between embryogenic callus (EC) and nonembryogenic callus (NEC) derived from mature seed embryo of rice (Oryza sativa L. cv Donggin). Three EC-specific transcripts were identified by differential display of amplified cDNAs. Specific expression of two partial cDNAs, designated as REC1 and REC2, respectively, was confirmed by a northern blot analysis. Partial nucleotide sequence of the clone REC1 showed no homology with any known genes, but partial amino acid sequence deduced from the clone REC2 exhibited 55-82% homology with nickel-cobalt-resistant proteins identified from a bacterium, Alcaligenes eutrophus CH34.

A case of superior vena cava syndrome caused by Klebsiella pneumoniae

A 27 yr old man presented with productive cough, fever and manifestations of superior vena cava syndrome. He was an alcoholic but had been in good health until 3 days prior to admission. The physical examination, the chest radiograph and the results of the sputum culture were compatible with Klebsiella pneumoniae pneumonia of the right upper lobe. The superior vena cava scintigram using technetium-99m showed near total occlusion of the superior vena cava, while sputum cytology, chest computed tomography, and bronchoscopy were all negative for malignant aetiology. Antibiotic therapy brought about slow resolution of the pneumonia and also of the superior vena caval obstruction. The follow-up scintigram showed normalized venous flow of the superior vena cava. To our knowledge, this is the first case of superior vena cava syndrome developed in probable association with Klebsiella pneumoniae pneumonia.

The effect of nisin concentration and nutrient depletion on nisin production of Lactococcus lactis

The kinetics of nisin production was studied in batch cultures using a construct of Lactococcus lactis subsp. lactis C2SmPrt-, containing a transposon (TnNip) that encodes nisin production. The introduction of TnNip into C2SmPrt- significantly lowered the specific growth rate and the maximum A620 reached was reduced from 15.2 to 11.0. The effect of nisin concentration and nutrient depletion on nisin production of the construct, C2SmPrt-(TnNip), was examined. Nisin production was found to be inhibited by high concentrations of nisin, when grown in excess nutrient, even though growth of the culture continued because nutrient limitation was not operating. However, in low nutrient concentrations nisin production was limited by nutrient depletion. The specific growth rate of C2SmPrt-(TnNip) was altered, by using different nutrient concentrations and different sugars, in order to examine the relationship between nisin production and growth. Nisin production was shown to be growth-associated for most of growth, but near the end of growth, when the specific growth rate was 0.05 h-1 or less, the production ceased.

The elusive Angelman syndrome critical region

DNA mapping studies in two families provide further information on the Angelman syndrome critical region, which has recently been defined by the gene UBE3A. The first family has probable familial Angelman syndrome with a maternally imprinted inheritance pattern. A 5 year old girl with this disorder has a 14 year old brother and an 11 year old male cousin who have less typical clinical features. DNA microsatellite analysis has shown that the three share a common segment of the same grandpaternal chromosome 15q11-q13 that overlaps with UBE3A. The child with typical Angelman syndrome has an additional maternal recombination 5' to UBE3A. The second family is a mother and son both of whom have mental retardation but no other features of Angelman syndrome despite an extensive DNA deletion on the telomeric side of UBE3A. Together, the two families identify a region between loci D15S210 and D15S986 which forms part of the Angelman syndrome critical region. A new microsatellite (D15S1234) is described which can be used in place of the LS6-1 marker at locus D15S113.

Nisin production by Lactococcus lactis using two-phase batch culture

Nisin production by Lactococcus lactis subsp. lactis C2SmPrt-(TnNip) was investigated using two-phase batch culture. A solvent (phenyl-methyl silicone oil) was introduced in addition to the aqueous phase. The partition coefficient of this solvent in aqueous nisin varied as the cultivation medium changed, with a minimum value being 1.04. The two-phase batch culture supported a 21% increase in growth and a 24% increase in the level of nisin produced compared to the single-phase batch culture.

Expression of transforming growth factor beta type II receptor reduces tumorigenicity in human gastric cancer cells

Expression of transforming growth factor beta (TGF-beta) receptor type II (RII) is required for the growth-inhibitory effects of TGF-beta on proliferating epithelial cells. TGF-beta RII mutations have been identified in a broad spectrum of human epithelial malignancies, including colon and gastric cancers, and are highly correlated with development of TGF-beta resistance in cell lines derived from these tumors. In this study, the role of TGF-beta RII in regulating the tumorigenic potential of the SNU-638 human gastric cancer cell line was investigated by infecting these cells with retroviral construct (MFG) expressing TGF-beta RII. The SNU-638 cell line displays the DNA replication error phenotype and encodes a truncated, inactive TGF-beta RII protein. Infection of these cells with retroviral constructs expressing wild-type TGF-beta RII led to significant increases in TGF-beta RII mRNA and protein expression. These cells responded to exogenous TGF-beta with reduced proliferation compared to that of control cells infected with retroviral vector expressing chloramphenicol acetyltranferase. Addition of TGF-beta-neutralizing antibodies led to increased proliferation of wild-type TGF-beta RII-expressing SNU-638 cells but had no effect on control cells. The latter finding suggests that TGF-beta acts in an autocrine fashion to inhibit cell proliferation in SNU-638 cells. When transplanted into athymic nude mice, wild-type TGF-beta RII-expressing SNU-638 cells showed decreased and delayed tumorigenicity compared with control cells. This study suggests a strong association between the expression of wild-type TGF-beta RII and the degree of malignancy in human gastric cancer cells.

A novel threonine --> proline mutation at the end of 2B rod domain in the keratin 2e chain in ichthyosis bullosa of Siemens

We report a novel mutation in a case of ichthyosis bullosa of Siemens that results in a threonine --> proline substitution in a novel location, codon 485 in a highly conserved residue position of the IATYRKLLEGE consensus motif at the end of the 2B rod domain segment of the keratin 2e chain. The disease phenotype is consistent with the inappropriate substitution of a proline near the end of the rod domain, because it lies near the predicted molecular overlap region of coiled-coil molecules, which is critical for the maintenance of the structural integrity of keratin intermediate filaments.

Identification of a cold shock gene in lactic acid bacteria and the effect of cold shock on cryotolerance

When Lactic Acid Bacterial cultures were frozen at -20 degrees C for 24 h, the cell viability decreased drastically, but when they were cold shocked at 10 degrees C for 2 h prior to freezing, viability improved significantly for the Lactococcus lactis subsp. lactis strains (25-37%) and Pediococcus pentosaceus PO2 (18%), but not for the Lactococcus lactis subsp. cremoris strains tested or for one strain of Lactobacillus helveticus LB1 and Streptococcus thermophilus TS2. When the period for cold shock was extended to 5 h, the viability increased even further for those strains that displayed cold shock cryotolerance. Use of degenerate PCR primers based on the major cold shock protein (csp) of both Escherichia coli and Bacillus subtilis resulted in PCR products from all strains tested. The PCR product from Lactococcus lactis ssp. lactis M474 was cloned and sequenced, and the deduced amino acid sequence displayed a high sequence similarity to other csp's. Use of PCR primers based on the M474 sequence resulted in PCR products being produced only from the lactococcal strains studied and not from the Lactobacillus helveticus, Streptococcus thermophilus, or Pediococcus pentosaceus strains tested.

Evaluation of an activated carbon felt passive sampler in monitoring organic vapors

Using an activated carbon felt (ACF, KF-1600), the applicability of an ACF passive sampler in monitoring organic vapors was evaluated. The evaluated results of the ACF passive sampler were compared with those of a 3 M (Model 3500) passive sampler. At low-humidity condition (8 +/- 3% RH), the sampling rates of the ACF passive sampler for volatile organic vapors were within the range of +/-25% from the results of a charcoal tube, which was the reference method recommended by NIOSH. However, at high humidity condition (90 +/- 5% RH), even though the sampling rates for toluene, MIBK, and PCE were within the range of +/-25%, the sampling rates of ACF sampler for n-hexane and MEK decreased steeply with time after being high at the beginning of the exposure time. Under this condition, the sampling rate of the 3 M passive sampler for MEK was also high at the beginning of the exposure time. In case of the ACF passive sampler, the sampling rates of the relatively strong adsorbates such as toluene, MIBK, and PCE were much less affected by humidity than those of n-hexane and MEK which were weak adsorbates.

MR of childhood metachromatic leukodystrophy

PURPOSE

To investigate the MR findings of childhood metachromatic leukodystrophy (MLD).

METHODS

Nine MR imaging studies in seven children (five girls and two boys, 10 to 32 months old) with MLD were evaluated retrospectively for the extent and progression of white matter abnormalities and the presence of contrast enhancement.

RESULTS

All seven cases showed symmetric, confluent high signal intensity on T2-weighted images in the periventricular white matter and centrum semiovale. A posterior predominance of white matter abnormalities was noted in all cases. Although initially spared from demyelination in all cases, in one case, the subcortical U fibers were later involved in demyelination of follow-up MR studies. Other sites of involvement were the genu (n = 5) and splenium (n = 6) of the corpus callosum, the posterior limbs of the internal capsule (n = 5), the descending pyramidal tracts (n = 4), the claustrum (n = 4), and the cerebral white matter (n = 2); diffuse brain atrophy was seen in two cases. No enhancement of the lesion was seen on any of the five postcontrast examinations. A "tigroid" pattern, previously described in cases of Pelizaeus-Merzbacher disease, was noted in the centrum semiovale in six cases.

CONCLUSION

In late-infantile MLD, demyelination is more prominent in the occipital region. In addition to demyelination of the periventricular white matter, common manifestations include a "tigroid" pattern and involvement of the corpus callosum, the internal capsule, and the corticospinal tract.

Pulmonary tuberculosis in children: evaluation with CT

OBJECTIVE

The purpose of our study was to describe the CT findings of pulmonary tuberculosis in children and to define indications for the use of CT.

MATERIALS AND METHODS

CT findings in 41 consecutive children with confirmed tuberculosis were retrospectively analyzed by two radiologists. Chest radiographs and medical records were also reviewed to determine whether additional information provided by CT scans had altered clinical management of the disease.

RESULTS

Mediastinal and hilar lymphadenopathy was seen in 34 patients (83%). In 29 of these patients, enlarged nodes had low-attenuation centers and enhancing rims. In the five other patients, enlarged nodes had calcification. Segmental (n = 12) or lobar (n = 8) air space consolidation was seen in 20 patients (49%), nodules of bronchogenic spread were seen in 12 patients (29%), and miliary nodules were seen in seven patients (17%). Bronchial (n = 15), pleural (n = 7), pericardiac (n = 1), or chest wall (n = 1) complications of tuberculosis were seen in 22 patients (54%). In eight (20%) of 41 patients, a diagnosis of tuberculosis was suggested only on CT scans, which revealed low-attenuation nodes with rim enhancement, calcifications, and nodules of bronchogenic spread or miliary nodules. These findings were not seen on chest radiographs. In 15 patients (37%), CT scans provided information that altered clinical management. Also two of these patients underwent surgery because of pleural and chest wall complications that were seen only on CT scans.

CONCLUSION

Mediastinal or hilar lymphadenopathy revealed as low-attenuation nodes with rim enhancement or calcification was the most characteristic CT finding of pulmonary tuberculosis in children. CT can be useful when tuberculosis or its complications are suspected in children and the radiographic findings are normal or inconclusive.

Purification, characterization, and cDNA cloning of a novel alpha-galactosidase from Mortierella vinacea

A novel alpha-galactosidase, designated alpha-galactosidase II, was isolated from the culture filtrate of Mortierella vinacea. The molecular size of the purified enzyme estimated by gel filtration was 60 kDa, which agreed with that, 51-62 kDa, estimated by SDS-PAGE. The enzyme was thermolabile at neutral pH, but the addition of BSA to the enzyme solution at the concentration of 0.01% increased its stability considerably. The enzyme appears to be novel because it showed a distinct substrate specificity from other microbial alpha-galactosidases on galactomanno-oligosaccharides, prepared from galactomannan, that is, the enzyme liberated not only side-chain alpha-galactosyl residue from 6(3)-mono-alpha-D-galactopyranosyl-beta-1,4-D-mannotetraose but also terminal alpha-galactosyl residue from 6(3)-mono-alpha-D-galactopyranosyl-beta-1,4-D-mannotriose. In addition, the enzyme acted on galactomannans effectively. alpha-Galactosidase II cDNA was cloned and its nucleotides sequenced. The deduced amino acid sequence showed that the mature enzyme consisted of 376 amino acid residues with a molecular mass of 41,334 Da. The derived amino acid sequence of the enzyme showed 31-49% sequence similarity with those of alpha-galactosidases from other origins.

Mutation of ras oncogene in gastric adenocarcinoma: association with histological phenotype

In order to explore the role of ras oncogene in gastric carcinomas from Korean patients, we examined the frequency of point mutations all three ras oncogenes (Ki-, Ha-, and N-ras). A total of 57 DNA samples were prepared from 3 gastric carcinoma cell lines, 10 malignant ascites, and 44 frozen gastric tumor tissues. Exons 1 and 2 of each ras oncogene were amplified by polymerase chain reaction (PCR), and analyzed by single strand conformation polymorphism (SSCP) and direct sequencing. Mutated ras genes were detected in 6 out of 57 samples (10%). One cell line and 2 tumors showed a mutation at exon 1 of Ki-ras. N-ras mutations were also detected at exon 1 of 3 tumors. Histologically, all the ras mutation cases exhibited a diffuse phenotype. In summary, we performed a comprehensive analysis to investigate the mutation of all three ras oncogenes in gastric carcinoma. The results demonstrate infrequent mutations of Ki- and N-ras which may favor the development of diffuse type gastric carcinomas, implicating a different genetic pathway in diffuse and intestinal type gastric carcinomas.

Poorly differentiated ("insular") carcinoma of the thyroid gland--two cases report

Poorly differentiated ("insular") carcinoma of the thyroid shares insular, trabecular, and solid histological patterns that are different from those of papillary, follicular, medullary, and anaplastic varieties. This tumor is situated morphologically and biologically in the intermediate position between the well differentiated (papillary and follicular) and the totally undifferentiated (anaplastic) thyroid tumors. We report two cases of insular carcinoma of the thyroid, occurring in 39-year-old and 52-year-old women. Grossly, these cases showed a lobulated mass with fibrous septa. The histologic finding showed characteristic "insular" growth pattern with focal follicular or papillary areas. Thyroglobulin was demonstrated within cytoplasmic paranuclear vacuoles of the neoplastic cells. Calcitonin and amyloid were not demonstrated. The aspiration cytology showed high cellularity, low grade of atypia, presence of clusters, nests, and trabeculae of cells with poorly outlined cytoplasm. The ultrastructural finding showed primordial cells having cytoplasmic organelles such as rough endoplasmic reticulum, mitochondria, and free ribosomes. We believe that its separation from other types of thyroid carcinoma will lead to a more accurate estimate of its biologic behavior and a more appropriate therapeutic approach.

Overexpression of cyclin D1 correlates with early recurrence in superficial bladder cancers

Cyclin D1 is a cell cycle regulator essential for G1 phase progression and is frequently overexpressed in several human tumour types as a consequence of gene amplification or chromosomal rearrangements. We analysed the expression of cyclin D1 in 75 patients with transitional cell carcinoma (TCC) to investigate the possible relationship between its expression and clinical outcome as well as histopathological findings using the immunohistochemical method. We observed strong staining (++, > 50% positive cells) for cyclin D1 in 19 cases (25.3%) and weak staining (+, 5-50% positive cells) in 19 cases (25.3%). Overexpression of cyclin D1 was not associated with tumour invasion. No significant association was found between overexpression of cyclin D1 and tumour grade (P > 0.05). We assessed the differences of disease-free interval in superficial tumours and actuarial survival probability in invasive tumours according to the status of cyclin D1 expression. Tumours with (++) staining for cyclin D1 recurred much more rapidly than (-) and/or (+) staining tumours (P < 0.01 for - vs ++; P < 0.05 for + vs ++). However, overexpression of cyclin D1 was not associated with a shortened overall survival of patients with invasive tumours (P < 0.1). These results suggest that genetic alteration of cyclin D1 appears to be an early event in the tumorigenesis of bladder TCC and is associated with early recurrence in superficial tumours.

Congenital cystic adenomatoid malformation of the lung: CT-pathologic correlation

OBJECTIVE

The purpose of this study was to correlate CT findings of congenital cystic adenomatoid malformation (CCAM) of the lung with pathologic findings.

MATERIALS AND METHODS

CT scans of CCAM from 21 consecutive patients were analyzed retrospectively by two chest radiologists who achieved consensus. Pathologic findings were assessed by an experienced pulmonary pathologist. Preoperative CT findings were correlated with pathologic findings.

RESULTS

Areas with small cysts (< 2 cm in diameter) were seen on CT scans in 19 (90%) of 21 patients, whereas areas with a large cyst (> 2 cm in diameter) were observed in 18 patients (86%). Areas of consolidation (n = 9; 43%) with heterogeneous attenuation on enhanced scans and areas of low attenuation (lower than normal lung) around cystic lesions (n = 6; 29%) were also seen on CT scans. The diameter of the largest cyst seen on CT scans in each patient ranged from 1.0 to 8.0 cm (median, 4.5 cm). Cysts that CT showed to be filled with air, fluid, or both correlated completely with the pathologic findings. Areas of consolidation corresponded histologically to areas of glandular or bronchiolar structures with or without areas of endogenous lipoid or organizing pneumonia or mucus plugs. Areas of low attenuation corresponded to areas of microcysts blended with normal lung parenchyma.

CONCLUSION

CT scans show the variable internal characteristics of CCAM and can suggest the underlying pathology of such lesions.

Involvement of the gallbladder in childhood metachromatic leukodystrophy: ultrasonographic findings

The purpose of this study was to analyze the peculiar involvement of the gallbladder in childhood metachromatic leukodystrophy. Seven consecutive children (four boys, three girls; age range, 9 to 58 months old; mean age, 24.3 months) with biochemically confirmed metachromatic leukodystrophy were studied with abdominal ultrasonography. Four of them showed abnormal findings, such as diffuse thickening of the gallbladder wall (more than 3 mm thick), sludge-like echogenic material, or papillary polypoid ingrowth of inner wall obliterating the lumen. In childhood metachromatic leukodystrophy, the characteristic abnormality of the gallbladder on ultrasonography may serve as an ancillary diagnostic clue to supplement the clinical and MR imaging findings, facilitating the differential diagnosis from the other, similar leukodystrophies.

A novel H1 mutation in the keratin 1 chain in epidermolytic hyperkeratosis

We report a novel mutation in a case of epidermolytic hyperkeratosis that results in a proline for arginine substitution in the penultimate residue position of the H1 subdomain of the keratin 1 chain, which is near the beginning of the rod domain. This causes a severe clinical disease classified as PS-2. Therefore, the H1 subdomain is probably equally important for the maintenance of keratin intermediate filament integrity as the rod domain. Since earlier concepts had implied that mutations in the H1 subdomain produce milder disease, this case suggests that attempts to correlate mutations with disease presentation remain problematic.

CT and US findings of pancreatoblastoma

PURPOSE

Our goal was to evaluate US and CT findings of pancreatoblastoma.

METHOD

Three US and four CT scans before surgery and one follow-up CT after surgery were reviewed in four patients (two female, two male) with pathologically proven pancreatoblastoma. The mean age of the patients was 4 years (range 2-5 years). The masses were analyzed for origin, US and CT architecture, presence of calcification, enhancement pattern, and metastatic spread.

RESULTS

In two patients, the tumors arose from the pancreatic head and in one patient from the pancreatic tail. The mean largest diameter of the masses was 10 cm, ranging from 5 to 14 cm. Sonography obtained from three cases showed mixed echogenic solid mass. On the CT scan, all tumors were huge, lobulated masses with heterogeneous attenuation. One tumor contained numerous foci of calcification. On the enhanced CT scan, three tumors showed multiloculated appearance by enhancing internal septations. There was no evidence of metastasis to distant organ or abdominal lymph node in any case.

CONCLUSION

We suggest that the most common US finding of pancreatoblastoma is a mixed echogenic, solid mass inseparable from the pancreas, and the most common CT finding is a relatively well defined, lobulated, huge mass with multiloculated appearance by enhancing septae in or near the lesser sac.

Mitochondrial myopathy-encephalopathy-lactic acidosis-and strokelike episodes (MELAS) syndrome: CT and MR findings in seven children

OBJECTIVE

The purpose of this study was to describe the imaging characteristics of mitochondrial myopathy-encephalopathy-lactic acidosis-and strokelike episodes (MELAS) syndrome.

MATERIALS AND METHODS

Twelve CT scans and 15 MR images were retrospectively reviewed in seven patients with proven MELAS syndrome. Follow-up studies were performed in all patients, and the total follow-up period ranged from 3 months to 3 years. Images were analyzed in terms of lesion distribution, enhancement pattern, presence of mass effect or atrophy, calcification, and changes on follow-up studies.

RESULTS

CT and MR imaging showed multiple cortical and subcortical infarctlike lesions, which crossed vascular boundaries, and various degrees of generalized cerebral and cerebellar atrophy. Lesions were distributed in the posterior, parietal, and occipital areas in six patients, the putamen in five, the caudate nucleus in two, the thalamus in two, the frontal lobe in two, the globus pallidus in one, and the brainstem in one. Contrast enhancement was noted in two of seven cases on MR images and in three of five cases on CT scans. In the early stage, infarctlike lesions showed swelling and mass effect. Lesions resolved with or without local tissue loss in five patients, and new lesions appeared in another part of the brain in five patients. Generalized atrophy progressed in six cases and was most severe in the posterior part of the cerebral hemispheres.

CONCLUSION

Our results indicate that imaging findings of multiple migrating infarctlike lesions that are not limited to a specific vascular territory, especially in the basal ganglia and posterior part of the cerebral hemisphere in children, are diagnostic of MELAS syndrome.

Establishment of sequence-tagged sites on 15q11-q13 by Alu-vector PCR cloning of YAC-generated fragments

Angelman syndrome (AS) is caused by the loss of function of undefined gene(s) on human chromosome 15. The majority of subjects have deletions involving maternally-derived chromosome 15q11-q13, and the shortest region of deletion overlap (SRO) has been localized to the region between D15S10 and D15S113. In this study, yeast artificial chromosomes (YACs), 6G-D4, 9H-D2 and 37D-F9, mapping within the AS SRO, were isolated from the ICI YAC library. Alu-vector PCR products were amplified from the YACs and from YACs A229A2 and A33F10 which had been obtained from the St. Louis YAC library. The PCR products were cloned and sequenced, and three new sequence-tagged sites were generated within the AS SRO, facilitating the characterization of gene(s) involved in the Angelman syndrome.