Synthesis of Microporous Silica Spheres

Spherical microporous silica powders with a narrow size distribution have been prepared by a precipitation technique involving the hydrolysis reaction of a silicon alkoxide in ethanol. The formation of the important microporosity has been investigated following two templating methods: the co-hydrolysis and condensation of two alkoxides, one of which presents porogen function, and the adsorption of an organic compound (glycerol) as the porogen. In both processes, the organic porogen is removed by a simple calcination. In the first method, the addition of more than 20 mol% of the porogen alkoxide, necessary for generating enough microporosity, disturbs completely the condensation process resulting in microporous, nonuniform silica particles of large size distribution. The best result has been obtained with the glycerol method where submicrometer-sized silica spheres with a very narrow size distribution and about 40 vol% porosity have been synthesized. The presence of glycerol during the synthesis considerably affects the precipitation mechanism, resulting in a larger mean particle size. The use of an aggregative growth model has successfully been employed to explain the effect of the porogen during particle formation. The precipitation mechanism of silica involves the aggregation between particles of similar size until a critical size is reached, resulting in a uniform particle size distribution. In the presence of glycerol, it has been shown that a second aggregative growth between still-nucleating primary particles and large particles occurred with increasing reaction time. This second aggregative growth appears at an intermediate stage of the precipitation process and is due to both the precipitation of smaller primary particles and the destabilization of the colloidal stability of the system. This explains why the final particle size reached in this system is larger compared to silica particles synthesized without glycerol and shows how glycerol is incorporated in the silica particles. The synthesis of silica microporous spheres of narrow size distribution, by varying particle size and porosity, should yield a wide range of aqueous silica slurries for particular chemical mechanical polishing applications. Copyright 2000 Academic Press.

Differential expression of four sweet potato peroxidase genes in response to abscisic acid and ethephon

Expression of four peroxidase (POD) genes, three anionic PODs (swpa1, swpa2 and swpa3), and one neutral POD (swpn1) isolated from suspension cultures of sweet potato (Ipomoea batatas) were analyzed by measuring the accumulation of transcripts in suspension cultured cells and leaves of sweet potato in response to the stress-related plant hormones abscisic acid (ABA) and ethephon (an ethylene generating chemical). The four genes responded differently to ABA (0.1 mM) and ethephon (0.1 mM) in cultured cells and leaves. In suspension cultures, ABA reduced the expression levels of swpa1, swpa2, and swpn1, but did not affect the level of swpa3. Ethephon strongly increased expression levels of swpa3 and swpn1, and slightly increased the level of swpa1. The expression level of swpa2 was reduced. Expression levels in intact leaves, however, were significantly changed by this treatment. Expression of the swpa1 and swpa2 genes was induced 15 min after ABA treatment, followed by a decrease to a basal level after 3 h. A strong re-expression occurred after 12 h. Expression of the swpa3 and swpn1 genes occurred from 3 to 24 h after treatment. All four genes were differentially expressed 12 h after ethephon treatment. The swpa2 gene was strongly expressed immediately after ethephon treatment. The results indicate that each POD gene is differentially regulated by ABA and ethylene in whole plants and in cultured cells in vitro.

Long-term outcome and growth rate of subtotally resected petroclival meningiomas: experience with 38 cases

OBJECTIVE

To evaluate the long-term outcome of a subtotally resected residual tumor and to assess its growth rate, we analyzed the records of 38 patients with residual petroclival meningioma.

METHODS

Clinical records and radiological findings of 38 cases of petroclival meningioma that were diagnosed and subtotally resected at Seoul National University Hospital between 1981 and 1997 were carefully reviewed. Follow-up imaging studies were reviewed, and Karnofsky performance scale scores at the last follow-up were recorded. The duration of follow-up ranged from 6 to 141 months (mean, 47.5 mo; median, 30 mo). Tumor progression and progression-free survival rates were assessed. The growth rate of a residual tumor was evaluated by measuring the equivalent diameter and the tumor volume serially; the tumor doubling time was calculated, and the predictive factors for determining the growth pattern in residual tumors and the prognosis were analyzed.

RESULTS

In 33 (87%) of the 38 patients, Karnofsky performance scale scores at the last follow-up were 80 or above. The median progression-free survival time among patients with subtotally resected tumors was 66 months, and the 5-year progression-free survival rate was 60%. The growth rate of residual tumors was low (volume increase, 4.94 cc/yr; diameter increase, 0.37 cm/yr). The mean tumor doubling time was 8 years. Although there were no significant predictive factors, age and extent of tumor resection seemed to influence the progression-free survival rate. Significant factors affecting the growth rate were age and occurrence of menopause.

CONCLUSION

Subtotal resection with or without radiation or radiosurgery should be considered as a suitable treatment option for patients with petroclival meningiomas, especially the elderly, because the growth rate of residual tumors is low.

Subcutaneous nodules attributed to nocardiosis in a renal transplant recipient on tacrolimus therapy

We report a renal transplant patient who suffered from disseminated nocardiosis after empirical tacrolimus rescue therapy for chronic allograft rejection. The nocardiosis presented initially as only mildly tender subcutaneous calf nodules without any other signs of inflammation nor constitutional upset, which later spread to the lung and brain causing bronchopneumonia and brain abscesses. The risk factors for nocardial infection in our patient include the use of potent immunosuppressive agents such as tacrolimus, poorly controlled diabetes mellitus and kidney dysfunction. She responded well to combination antibiotic therapy comprising parenteral meropenem, cefotaxime and oral minocycline. We conclude that in transplant recipients, especially those receiving newer and more potent immunosuppressive agents like tacrolimus, nocardial infection can present as apparently 'cold' subcutaneous nodules without any systemic upset. An associated brain lesion should be excluded even in patients without neurological symptoms.

Regulation of plasmin activity by annexin II tetramer

Annexin II tetramer (AIIt) is a major Ca(2+)-binding protein of the endothelial cell surface which has been shown to stimulate the tissue plasminogen activator (t-PA)-dependent conversion of plasminogen to plasmin. In the present report, we have examined the regulation of plasmin activity by AIIt. The incubation of plasmin with AIIt resulted in a 95% loss in plasmin activity. SDS-PAGE analysis established that AIIt stimulated the autoproteolytic digestion of plasmin heavy and light chains. The kinetics of AIIt-stimulated plasmin autoproteolysis were first-order, suggesting that binding of plasmin to AIIt resulted in the spontaneous autoproteolysis of the bound plasmin. AIIt did not affect the activity of other serine proteases such as t-PA or urokinase-type plasminogen activator. Furthermore, other annexins such as annexin I, II, V, or VI did not stimulate plasmin autoproteolysis. Increasing the concentration of AIIt on the surface of human 293 epithelial cells increased cell-mediated plasmin autoproteolysis. Thus, in addition to stimulating the formation of plasmin, AIIt also promotes plasmin inactivation. These results therefore suggest that AIIt may function to provide the cell surface with a transient pulse of plasmin activity.

Cdc2 and Cdk2 kinase activated by transforming growth factor-beta1 trigger apoptosis through the phosphorylation of retinoblastoma protein in FaO hepatoma cells

The signaling pathway leading to TGF-beta1-induced apoptosis was investigated using a TGF-beta1-sensitive hepatoma cell line, FaO. Cell cycle analysis demonstrated that the accumulation of apoptotic cells was preceded by a progressive decrease of the cell population in the G(1) phase concomitant with a slight increase of the cell population in the G(2)/M phase in response to TGF-beta1. TGF-beta1 induced a transient increase in the expression of Cdc2, cyclin A, cyclin B, and cyclin D1 at an early phase of apoptosis. During TGF-beta1-induced apoptosis, the transient increase in cyclin-dependent kinase (Cdk) activities coincides with a dramatic increase in the hyperphosphorylated forms of RB. Treatment with roscovitine or olomoucine, inhibitors of Cdc2 and Cdk2, blocked TGF-beta1-induced apoptosis by inhibiting RB phosphorylation. Overexpression of Bcl-2 or adenovirus E1B 19K suppressed TGF-beta1-induced apoptosis by blocking the induction of Cdc2 mRNA and the subsequent activation of Cdc2 kinase, whereas activation of Cdk2 was not affected, suggesting that Cdc2 plays a more critical role in TGF-beta1-induced apoptosis. In conclusion, we present the evidence that Cdc2 and Cdk2 kinase activity transiently induced by TGF-beta1 phosphorylates RB as a physiological target in FaO cells and that RB hyperphosphorylation may trigger abrupt cell cycle progression, leading to irreversible cell death.

A new autoantigen reactive with prediabetic nonobese diabetic mice sera

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

Role of annexin II tetramer in plasminogen activation

The enzymatic cascade triggered by activation of plasminogen has been implicated in a variety of normal and pathologic events, such as fibrinolysis, wound healing, tissue remodeling, embryogenesis, and the invasion and spread of transformed tumor cells. Recent data established that the Ca(2+)- and phospholipid-binding protein, annexin II heterotetramer (AIIt) binds tissue-type plasminogen activator (tPA), plasminogen, and plasmin, and dramatically stimulates the tPA-dependent conversion of plasminogen to plasmin in vitro. Interestingly, the binding of plasmin to AIIt can inhibit the activity of the enzyme, suggesting that plasmin bound to the cell surface is regulated by AIIt. The existing experimental evidence suggests that AIIt is the key physiological receptor for plasminogen on the extracellular surface of endothelial cells.

Association of benzo[a]pyrene-diol-epoxide-deoxyribonucleic acid (BPDE-DNA) adduct level with aging in male smokers and nonsmokers

We used our new flow cytometric method to measure benzo[a]pyrene-diolepoxide-deoxyribonucleic acid adduct levels in peripheral lymphocytes from healthy male smokers and nonsmokers. Smokers who had pack-years of 20 or more had significantly higher mean benzo[a]pyrene-diol-epoxide-deoxyribonucleic acid adduct levels than nonsmokers. In smokers, the adduct levels were correlated significantly with age, years of smoking, and pack-years, whereas daily tobacco consumption was not correlated with adduct levels. We also found a positive relationship between age and benzo[a]pyrene-diol-epoxide-deoxyribonucleic acid adduct levels in nonsmokers. Passive exposure to tobacco smoke was not associated with adduct levels. The results of our study indicate that benzo[a]pyrene-diol-epoxide-deoxyribonucleic acid adduct levels may be closely related to aging and that tobacco smoking-as well as other environmental factors-may play a role in the benzo[a]pyrene-diol-epoxide-deoxyribonucleic acid adduct formation.

Production and characterization of monoclonal antibodies to porcine brain pyridoxal kinase

Six monoclonal antibodies that recognize porcine brain pyridoxal kinase have been selected and designated as PK67, PK86, PK91, PK144, PK252 and PK275. A total of six monoclonal antibodies recognizing different epitopes of the enzyme were obtained, of which four inhibited the enzyme activity. When total proteins of porcine brain homogenate separated by SDS-PAGE were subjected to monoclonal antibodies, a single reactive protein band of molecular weight 39 kDa which comigrated with purified porcine pyridoxal kinase was detected. Using the anti-pyridoxal kinase antibodies as probes, the cross reactivities of brain pyridoxal kinase from human and other mammalian tissues and from avian sources were also investigated. Among human and all animal tissues tested, immunoreactive bands on Western blots appeared to have the same molecular mass of 39 kDa. These results indicate that mammalian brains contain only one major type of immunologically similar pyridoxal kinase, although some properties of the enzymes reported previously differed from one another.

The p11 subunit of the annexin II tetramer plays a key role in the stimulation of t-PA-dependent plasminogen activation

Annexin II tetramer (AIIt) is an important endothelial cell surface protein receptor for plasminogen and t-PA. AIIt, a heterotetramer, is composed of two p36 subunits (called annexin II) and two p11 subunits. In this report, we have compared the ability of the isolated p36 and p11 subunits to stimulate t-PA-dependent [Glu]plasminogen activation. The fluid-phase recombinant p11 subunit stimulated the rate of t-PA-dependent activation of [Glu]plasminogen about 46-fold compared to an approximate stimulation of 2-fold by the recombinant p36 subunit and 77-fold by recombinant AIIt. The stimulation of t-PA-dependent activation of [Glu]plasminogen by the p11 subunit was Ca2+-independent and inhibited by epsilon-aminocaproic acid. [Glu]Plasminogen bound to a p11 subunit affinity column and could be eluted with epsilon-aminocaproic acid. Both AIIt and the p11 subunit protected t-PA and plasmin from inactivation by PAI-1 and alpha2-antiplasmin, respectively. A peptide to the C terminus of the p11 subunit (85-Y-F-V-V-H-M-K-Q-K-G-K-K-96) inhibited the p11-dependent stimulation of t-PA-dependent plasminogen activation. In addition, a deletion mutant of the p11 subunit, missing the last two C-terminal lysine residues, retained only about 15% of the activity of the wild-type p11 subunit. Similarly, a mutant AIIt composed of the wild-type p36 subunit and the p11 subunit deletion mutant possessed about 12% of the wild-type activity. These results, therefore, suggest that the C-terminal lysine residues of the p11 subunit bind plasminogen and participate in the stimulation of t-PA-dependent activation of plasminogen by AIIt.

Gliomatosis cerebri: clinical features, treatment, and prognosis

To clarify clinical features and to elucidate prognostic factors and prognosis, the authors retrospectively analyzed 16 cases of gliomatosis cerebri treated at Seoul National University Hospital between January 1988 and December 1995. Age at diagnosis ranged from 19 to 62 (median 34) years and male to female ratio was 10:6. Most presented with headache or seizure, and the mean duration of symptoms was 12.8 months. A poorly defined diffuse high signal intensity lesion, extending in T2-weighted images for two lobes or more, was the characteristic magnetic resonance (MR) image finding. On postcontrast T1-weighted MR imaging, focal enhancement of the lesion was detected in five cases. All patients underwent histological confirmation by craniotomy (9 cases) or stereotactic biopsy (7 cases). Histologically, all patients had compatible findings of gliomatosis cerebri which are the widespread infiltration of neoplastic glial cells with minimal destruction of pre-existing structures. After histological diagnosis, external radiation therapy was begun except in one case, who declined this treatment. Fourteen patients completed the whole procedure and received the planned dose (mean 5780 cGy). Median survival time after diagnosis was 38.4 months. In univariate analysis, the Ki-67 labelling index (> 1) showed significant correlation with the length of survival (p = 0.006). It is suggested that 1) gliomatosis cerebri can be diagnosed by a combination of MR imaging findings and histological examination; 2) histological diagnosis and external radiation therapy might be a good treatment modality; 3) the Ki-67 labelling index correlates significantly with survival time.

Acute hemolytic crisis with fulminant hepatic failure as the first manifestation of Wilson's disease: a case report

We report a 27-year-old woman who developed Coombs' negative hemolytic anemia and fulminant hepatic failure as the initial manifestation of Wilson's disease. Unmeasurably low level of serum alkaline phosphatase provided a clue to the diagnosis of Wilson's disease. The diagnosis was established with the presence of Kayser-Fleischer ring, decreased serum ceruloplasmin level, and elevated urine and serum copper levels. In spite of repeated plasmapheresis, she died of multiorgan failure on the fifth hospital day.

A case of Marfan syndrome with acute monoblastic leukemia

We report on an 18-year-old man who had both acute monoblastic leukemia and Marfan syndrome. A diagnosis of Marfan syndrome was established by those characteristics of arachnodactyly, ectopia lentis, mitral valve prolapse, and mitral regurgitation. Findings on bone marrow examination of the patient showed that most of nucleated cells were monoblasts and immunophenotype of those cells showed CD13+, CD33+, CD56+, and HLA-DR+. To our knowledge, this is the second report of leukemia in Marfan syndrome in the world.

Determination of the solute removal index for urea by using a partial spent dialysate collection method

In 22 hemodialysis patients, during a dialysis session, the solute removal index (SRI) for urea obtained from the use of a partial spent dialysate collection method was compared with that derived from the use of a total spent dialysate collection technique. The partial spent dialysate collection method was used to harvest a small representative sample of the total spent dialysate. The volumes of spent dialysate collected by the partial and the total spent dialysate collection methods were 1.7 +/- 0.4 L and 129.6 +/- 15.3 L, respectively. The total amount of urea nitrogen removed by dialysis as estimated by the partial spent dialysate collection method was similar to that determined by the total spent dialysate collection approach. As a result, the SRI value for urea obtained by the partial spent dialysate collection method (namely, 63% +/- 8%) correlated very well (r = 0.95, P < 0.001) with that derived by the total spent dialysate collection technique (namely, 62% +/- 8%). Our data suggest that it is feasible to use a simple partial spent dialysate collection method to obtain SRI results in patients treated with hemodialysis.

Bacterial adhesion on PEG modified polyurethane surfaces

Polyurethane surface was modified with poly(ethylene glycol) (mol. wt. 1000, PEG1k) carrying terminal hydroxyl, amino and sulfonate groups, poly(ethylene glucol) (mol. wt. 3350, PEG3.4k) and PEG3.4k-Heparin, respectively. These surfaces were investigated for bacterial adhesion using S. epidermidis and E. coli in tryptic soya broth (TSB), brain heart infusion (BHI), and human plasma. All PEG modified surfaces reduced bacterial adhesion significantly and the adhesion level differs depending on surfaces as well as media. In the case of PEG1k surfaces, no reduction of S. epidermidis adhesion was demonstrated in TSB media, regardless of terminal functional groups of PEG1k. However, adhesion in plasma was reduced to the different degree, depending on terminal groups of PEG1k (least adhesion on sulfonated PEG surface). Relatively longer PEG surface (PEG3.4k) and PEG3.4k-heparin surface minimized bacterial adhesion in both media. In the case of E. coli adhesion, significant reduction in adherent bacteria was observed on all PEG1k, PEG3.4k, and PEG-heparin surfaces in both media compared to controls. In contrast, no reduction in bacterial adhesion was demonstrated on poly(propylene glycol) (PPG1k) grafted PU surface as compared to control PU. These results suggest that surface modification with PEG1k-SO3, PEG3.4k and PEG3.4k-heparin seems to be effective for prevention of bacterial adhesion and subsequent infection.

Flow cytometric measurement of benzo[a]pyrene-diol-epoxide-DNA adducts in normal human peripheral lymphocytes and cultured human lung cancer cells

DNA adducts are mainly detected by 32P-postlabeling and enzyme-linked immunosorbent assays. We have established a method for detection of benzo[a]pyrene-diol-epoxide (BPDE)-DNA adducts by flow cytometry, and have clarified the effects of the DNA adducts on cell-cycle progression and the relationship between cell-cycle phases and DNA adduct formation, using human peripheral lymphocytes and three human lung cancer cell lines. We measured the BPDE-DNA adduct levels in both lymphocytes and cancer cells by isolating nuclei, using a nuclear isolation buffer containing Triton X-100 and staining with a BPDE-DNA-specific monoclonal antibody and biotin-streptavidin fluorescein conjugates. BPDE did not affect cell-cycle progression in human peripheral lymphocytes. However, in human lung cancer cells exposed to > 1 microg/ml BPDE, accumulation of cells in the S phase was seen. Cells with DNA content greater than G2M (aneuploid cells) or cells with less than G1 DNA content (apoptotic cells) increased gradually with exposure to increasing BPDE concentrations, suggesting that BPDE may affect cell-cycle progression through binding to DNA. Thus, the measurement of DNA adducts by flow cytometry may provide new insights into carcinogenesis.

The role of annexin II tetramer in the activation of plasminogen

Annexin II tetramer (AIIt) is a major Ca2+-binding protein of endothelial cells which has been shown to exist on both the intracellular and extracellular surfaces of the plasma membrane. In this report, we demonstrate that AIIt stimulates the activation of plasminogen by facilitating the tissue plasminogen activator (t-PA)-dependent conversion of plasminogen to plasmin. Fluid-phase AIIt stimulated the rate of activation of [Glu]plasminogen about 341-fold compared with an approximate 6-fold stimulation by annexin II. AIIt bound to [Glu]plasminogen(S741C-fluorescein) with a Kd of 1. 26 +/- 0.04 microM (mean +/- S.D., n = 3) and this interaction resulted in a large conformational change in [Glu]plasminogen. Kinetic analysis established that AIIt produces a large increase of about 190-fold in the kcat, app and a small increase in the Km,app which resulted in a 90-fold increase in the catalytic efficiency (kcat/Km) of t-PA for [Glu]plasminogen. AIIt also stimulated the t-PA-dependent activation of [Lys]plasminogen about 28-fold. Furthermore, other annexins such as annexin I, V, or VI did not produce comparable activation of t-PA-dependent conversion of [Glu]plasminogen to plasmin. The stimulation of the activation of [Glu]plasminogen by AIIt was Ca2+-independent and inhibited by epsilon-aminocaproic acid. AIIt bound to human 293 cells potentiated t-PA-dependent plasminogen activation. AIIt that was bound to phospholipid vesicles or heparin also stimulated the activation of [Glu]plasminogen 5- or 11-fold, respectively. Furthermore, immunofluorescence labeling of nonpermeabilized HUVEC revealed a punctated distribution of AIIt subunits on the cell surface. These results therefore identify AIIt as a potent in vitro activator of plasminogen.

A case of chronic graft-versus-host-disease following allogeneic peripheral blood stem cell rescue for poor graft function after bone marrow transplantation

To overcome poor graft function after allogeneic bone marrow transplantation (BMT), the use of peripheral blood stem cells (PBSC) instead of bone marrow is gaining more popularity because of its advantages. There may, however, be an increased risk of graft-versus-host-disease (GVHD) because of the large number of lymphocytes present in a leukapheresis product. An 18-year-old man with severe aplastic anemia underwent an allogeneic BMT using his HLA-identical sister. After initial excellent graft take for 8 months, his blood counts gradually decreased to 2.8 x 10(9)/L of white cells and 28 x 10(9)/L of platelets with marrow cellularity of < 10%. After allogeneic granulocyte-colony stimulating factor mobilized PBSC rescue, the patient's blood counts recovered satisfactorily. Around 1 year after the boost, he developed chronic GVHD that responded to prednisolone and cyclosporin A. He is now well on low-dose steroids at day +1055 after PBSC rescue. The present case is the first experience of a long-term follow-up who underwent allogeneic PBSC rescue in Korea.

Inhibition of p53 transactivation function by the human T-cell lymphotropic virus type 1 Tax protein

Human T-cell lymphotropic virus type 1 (HTLV-1) is the etiologic agent for adult T-cell leukemia. HTLV-1 transforms lymphocytes, and there is increasing evidence that the virus-encoded protein, Tax, plays a primary role in viral transformation. We have shown that wild-type p53 in HTLV-1-transformed cells is stabilized. This study was initiated to directly analyze whether the p53 in HTLV-1-transformed cell lines was transcriptionally active and to identify the viral gene product responsible for stabilization and inactivation. Transfection experiments using a p53-responsive reporter plasmid and gamma-irradiation studies demonstrate that the wild-type p53 in HTLV-1-transformed cell lines is not fully active. Further, we demonstrate that the HTLV-1-transforming protein, Tax, stabilizes and inactivates p53 function. Cotransfection of Tax with p53 results in a greater than 10-fold reduction in p53 transcription activity. Using Ga14-p53 fusion proteins, we demonstrate that Tax inhibition of p53 transactivation function is independent of sequence-specific DNA binding. Moreover, Tax inhibits p53 function by interfering with the activity of the N-terminal activation domain (amino acids 1 to 52). We conclude that Tax is involved in the inactivation of p53 function and stabilization of p53 in HTLV-1-infected cells. The functional interference of p53 function by Tax may be important for transformation and leukemogenesis.

ICE-like protease (caspase) is involved in transforming growth factor beta1-mediated apoptosis in FaO rat hepatoma cell line

Transforming growth factor-beta1 (TGF-beta1) arrests growth and/or stimulates apoptosis of a variety of cells. The biochemical pathways involved in the apoptotic processes, however, remain poorly defined. TGF-beta1 induces DNA fragmentation together with morphological changes, which are characteristic of apoptosis in the FaO rat hepatoma cell line. Histones were remarkably enriched in lysates of these cells during TGF beta1-induced apoptosis. We identified U1-70 kd as a death substrate which is cleaved following TGF-beta1 treatment. The tetrapeptide caspase inhibitor carbobenzoxy-valyl-alanly-aspartyl-(beta-O-methyl)-fluoromethyl ketone (ZVAD-FMK) prevented TGF beta1-induced apoptotic DNA fragmentation and cleavage of the U1-70 kd protein, showing that caspase(s) are involved in TGF beta1-mediated apoptosis. To identify specific caspases involved in apoptosis induced by TGF-beta1 in FaO cells, proteolytic activation of several of these caspases and their substrates were studied as a function of time following TGF beta1-treatment. TGF beta1-treatment induced the progressive proteolytic processing of caspase-2 (ICH-1L/Nedd-2), whereas caspase-1 itself did not show any cleavage from the precursor. Pretreatment with ZVAD-FMK abrogated the maturation of caspase-2 and blocked the apoptotic progress. These results suggest that caspase-2, but not caspase-1, may play a crucial role in TGF beta1-induced apoptosis in these cells.

Annexin II tetramer inhibits plasmin-dependent fibrinolysis

In this paper, we have characterized the regulation of plasmin activity by annexin II tetramer (AIIt). Plasmin activity was measured by a fibrin lysis assay in which a fibrin polymer was produced from purified components and the extent of polymer lysis was determined by following changes in turbidity. Extrinsic lysis of the fibrin polymer, initiated by addition of tissue plasminogen activator (t-PA), was totally blocked if AIIt was present during fibrin polymer formation. Furthermore, fibrin polymer formed in the presence of AIIt was resistant to extrinsic lysis initiated by addition of plasmin. AIIt bound to fibrin polymer under conditions in which polymer lysis was inhibited. Plasmin-dependent extrinsic lysis of the fibrin polymer was also blocked if AIIt was present in the incubation medium, and under these conditions the amidolytic activity of plasmin, measured with an artificial substrate, was inhibited about 5-fold. In contrast, in the absence of fibrin, and at an AIIt/plasmin molar ratio of 526, the amidolytic activity of plasmin was inhibited by only 22.3% +/- 7.4% (mean +/- SD, n = 5) by AIIt. Plasmin-dependent fibrinolysis was only slightly inhibited if fibrin polymer was formed in the presence of annexins I, II, V, or VI. These results identify AIIt as an in vitro regulator of plasmin activity.

Pineal tumors: experience with 48 cases over 10 years

The authors retrospectively reviewed 48 patients treated at Seoul National University Hospital (SNUH) between 1986 and 1995. There were 35 children and 13 adults, accounting for 10.1% of 345 pediatric and 0.68% of 1914 adult brain tumors in SNUH during the same period. The 48 cases consisted of 33 cases of germ cell tumor (69%, GCT); 6 of pineoblastoma (PB, 12.5%); 3 of pineocytoma (PC, 6.3%); 3 of anaplastic astrocytoma (6.3%); 1 of astrocytoma; 1 of glioblastoma; and 1 of ependymoma. The median age was 13 years (range 1-59) and the male-to-female ratio was 3.36:1. The most frequent presenting symptom was due to increased intracranial pressure (90%), followed by Parinaud syndrome or diplopia (50%). Patients with a benign tumor, such as teratoma (TE), astrocytoma, or ependymoma, underwent surgery by the occipital transtentorial approach (OTT) for attempted radical resection without adjuvant therapy, while patients with immature teratoma (imTE), PC, and anaplastic astrocytoma underwent regional radiotherapy (RT) after debulking via OTT. Seven patients with nongerminomatous malignant GCT (NG-MGCT) and 3 with germinoma (GE) underwent craniospinal radiation only, 6 with GE, a NG-MGCT, and 2 with GE+TE received craniospinal radiotherapy (CSRT) after debulking via OTT. Three patients with GE, 4 with NG-MGCT, and 3 with PB underwent radiochemotherapy after debulking via OTT. Forty-four patients were followed up after treatment. The median follow-up period was 36 months. All patients with GE were alive after RT at 36 months (median) of follow-up (range 7-70 months). All with GE+TE and TE were alive. Three patients with PC or astrocytoma were also alive with stable or no evidence of disease. In 1 of the 3 cases of imTE there was a recurrence. However, 4 patients with NG-MGCT died, all of whom had undergone CSRT only; 2 PB patients were alive (12, 19 months), 1 in a moribund status (36 months), and 2 were dead (6, 60 months). The overall mean survival time with pineal tumors was 66 months and the 3-year survival rate was 84% with minimal posttreatment complications. It is concluded that pineal region tumors have male and childhood predominances, and the most common tumor is GCT. The majority of pineal region tumors are malignant. Pineal region tumors can be approached safely and effectively and the surgical complications are mostly transient. Their prognosis is dependent on the pathologies and treatment modalities.

Molecular cloning of a novel ubiquitin-specific protease, UBP41, with isopeptidase activity in chick skeletal muscle

A cDNA encoding a new ubiquitin-specific protease, UBP41, in chick skeletal muscle was cloned using an Escherichia coli-based in vivo screening method. Nucleotide sequence analysis of the cDNA containing an open reading frame of 1,071 base pairs revealed that the protease consists of 357 residues with a calculated molecular mass of 40,847 Da, and is related to members of the UBP family containing highly conserved Cys and His domains. Chick UBP41 was expressed in E. coli and purified from the cells to apparent homogeneity, using 125I-labeled ubiquitin-alphaNH-MHISPPEPESEEEEEHYC as a substrate. The purified enzyme behaved as an approximately 43-kDa protein under both denaturing and nondenaturing conditions, suggesting that it consists of a single polypeptide chain. Like other deubiquitinating enzymes, it was sensitive to inhibition by ubiquitin-aldehyde and sulfhydryl blocking agents, such as N-ethylmaleimide. The UBP41 protease cleaved at the C terminus of the ubiquitin moiety in natural and engineered fusions irrespective of their sizes; thus, it is active against ubiquitin-beta-galactosidase as well as ubiquitin C-terminal extension protein of 80 amino acids. UBP41 also released free ubiquitin from poly-His-tagged di-ubiquitin. Moreover, it converted poly-ubiquitinated lysozyme conjugates to mono-ubiquitinated forms of about 24 kDa, although the latter molecules were not further degraded to free ubiquitin and lysozyme. These results suggest that UBP41 may play an important role in the recycling of ubiquitin by hydrolysis of branched poly-ubiquitin chains generated by the action of 26 S proteasome on poly-ubiquitinated protein substrates, as well as in the production of free ubiquitin from linear poly-ubiquitin chains and of certain ribosomal proteins from ubiquitin fusion proteins.

Protection of 5alpha-dihydrotestosterone against TGF-beta-induced apoptosis in FaO cells and induction of mitosis in HepG2 cells

Administration of TGF-beta1 to both FaO and HepG2 cells significantly induced apoptosis, particularly in FaO cells. Degradation of genomic DNA in FaO cells was rapidly induced by treatment with TGF-beta1 (5 ng/ml) for only 4 hr. 5alpha-dihydrotestosterone (DHT, 25 nM) alone did not affect any significant changes in cell viability and in nuclei of FaO cells; however, pre-treatment with DHT protected genomic DNA degradation induced by TGF-beta1 for 14 hr. Simultaneous treatment with DHT plus TGF-beta1 (D + T) inhibited TGF-beta-induced apoptosis by approximately 50% in FaO cells. On the other hand, D + T treatment increased mitosis in actively growing HepG2 cells. Thus, it is reasonable to conclude that DHT gives growth advantage to hepatocellular-carcinoma cells by inhibiting TGF-beta-induced DNA fragmentation in FaO cells and by inducting mitosis in HepG2 cells.

Verruciform xanthoma of the oral mucosa: an immunohistochemical and ultrastructural study of two cases

Verruciform xanthoma is an uncommon benign lesion of unknown aetiology and pathogenesis. Two cases of verruciform xanthoma are presented together with an immunohistochemical and ultrastructural study. One case co-occurred with an odontogenic keratocyst which, to our knowledge, has not been previously reported, and another case occurred on masticatory mucosa with an asymptomatic, granular, exophytic lesion causing a cleft-like gingival recession. In an immunohistochemical study using antibodies to macrophage (CD 68[KP1]), alpha-1-antitrypsin, vimentin, desmin, keratin, neuron-specific enolase (NSE) and S-100 protein, the characteristic foam cells of verruciform xanthoma showed strong positive staining for CD 68[KP1] and vimentin and weak positive staining for alpha-1-antitrypsin, while the other antibodies were negative. As in previous studies, S-100 protein positive dendritic cells were detected in lesional connective tissue. In addition, the ultrastructural findings revealed characteristics of macrophages containing varying sized lipid vacuoles and degenerating epithelial cells. These findings support the concepts that the foam cells in verruciform xanthoma are of monocyte-macrophage lineage and that the epithelial degeneration from uncertain causes may be related to the pathogenesis of the lesion.

Central neurocytoma: the role of radiation therapy and long term outcome

BACKGROUND

It has been suggested that the biologic behavior of central neurocytoma is indolent, although little is known regarding the role of radiation therapy and long term outcome. To clarify the role of radiation therapy and long term outcome, the authors retrospectively analyzed 15 cases of central neurocytoma.

METHODS

Clinical records and radiologic findings of 15 cases of central neurocytoma diagnosed at Seoul National University Hospital between January 1982 and February 1995 were carefully reviewed. The duration of follow-up was from 18-168 months (mean, 52 months); follow-up images were reviewed and the patient's Karnofsky performance scale (KPS) was assessed up to the time of last follow-up.

RESULTS

The age of the patients ranged from 15 to 60 years (mean, 25 years) and the male to female ratio was 11:4. Macroscopic total resection of the tumor was performed in seven patients, two of whom received fractionated radiation therapy. Subtotal removal of the tumor was performed in eight patients, five of whom received this same therapy. In 2 of the 5 patients who did not receive radiation therapy after macroscopic total resection, the tumors recurred 8 and 21 months after surgery, respectively; in contrast, recurrence was not detected in the 2 patients who received fractionated radiation therapy after macroscopic total resection. In all five patients who received fractionated radiation therapy after subtotal resection, the tumor shrank (n = 3) or disappeared (n = 2) during the postsurgical follow-up period ranging from 27-113 months; the tumor began to shrink from 6 months to 2 years after radiation. No change was found in the three patients who did not receive radiation therapy after subtotal resection. At the time of last follow-up, the KPS was greater than 90 in all patients except one who required assistance in his daily activities because of complications from radiation therapy.

CONCLUSIONS

It is suggested that even if the biologic behavior of a central neurocytoma is benign, radiation therapy appears to have an effect on tumor control. However, it should be carefully decided whether to use radiation therapy for a residual tumor because radiation can cause delayed complications and the clinical course of subtotally resected patients who do not receive radiation therapy is extremely benign.

Air pollution, temperature, and regional differences in lung cancer mortality in Japan

In this study, the authors investigated regional differences in lung cancer mortality in Japan, and, based on data acquired between 1970 and 1990 for 47 Japanese prefectures, estimated the relationship between regional lung cancer mortality and air pollution and/or temperature. Investigators used data for nitrogen dioxide, sulfur dioxide, motor vehicle density, tobacco expenditure, and temperature as independent variables for age-adjusted lung cancer death rates. The age-adjusted lung cancer death rates were higher in the southern geographical block of Japan (i.e., approximately 1.2-fold in males and 1.1-fold in females) and in the northern block (approximately 1.2-fold in males) than in the central block. The regional differences in the age-adjusted lung cancer death rates were explained by nitrogen dioxide and temperature. Temperature caused a greater effect (regression coefficients) of nitrogen dioxide on the age-adjusted lung cancer death rates than did nitrogen dioxide alone in the southern block (i.e., approximately 1.3-fold in males and 1.2-fold in females). These results provide the first evidence of a possible synergistic interaction between air pollution and high temperature on lung cancer mortality.

Neuronal Cdc2-like kinase (Nclk) binds and phosphorylates the retinoblastoma protein

The tumor suppressor retinoblastoma protein (RB) plays a central role in cellular growth regulation, differentiation, and apoptosis. Phosphorylation of RB results in a consequent loss of its ability to inhibit cell cycle progression. However, how RB phosphorylation might be regulated in apoptotic or postmitotic cells, such as neurons, remains unclear. Here we report that neuronal Cdc2-like kinase (Nclk), composed of Cdk5 and a neuronal Cdk5 activator (p25(nck5a)), can bind and phosphorylate RB. Since RB has been shown recently to associate with D-type G1 cyclins and viral oncoproteins through a common peptide sequence motif of LXCXE, Nclk binding may be mediated by a related sequence motif (LXCXXE) found in p25(nck5a). We demonstrate (i) in vitro binding of bacterially expressed p25(nck5a) to a GST-RB fusion protein, (ii) coprecipitation of GST-RB and reconstituted Cdk5.p25(nck5a), and (iii) phosphorylation of GST-RB by bacterially expressed Cdk5.p25(nck5a) kinase and by Cdk5.p25(nck5a) kinase purified from bovine brain. Finally, we show that immunoprecipitation of RB from embryonic mouse brain homogenate results in the coprecipitation of Cdk5 and that Cdk5 kinase activity is maximal during late embryonic development, a period when programmed cell death of developing neurons is greatest. Taken together, these results suggest that Nclk can bind to and phosphorylate RB in vitro and in vivo. We infer that Nclk may play an important role in regulating the activity of RB in the brain, including perhaps in apoptosing neurons.

Interaction of human T-cell lymphotropic virus type I Tax, Ets1, and Sp1 in transactivation of the PTHrP P2 promoter

We have previously shown that the parathyroid hormone-related protein (PTHrP) promoter contains binding sites for transcription factors Ets1 and Sp1 and that human T-cell lymphotropic virus type I (HTLV-I) Tax cooperates with Ets1 to transactivate the PTHrP P2 promoter. Using the yeast two-hybrid interaction system, we now provide evidence that Tax interacts with Ets1. Moreover, a double mutation (D22A,C23S) in the Tax protein that abrogated the Tax/Ets1 interaction also inhibited the Tax/Ets1 cooperative effect, suggesting that the interaction between Tax and Ets1 is important for transactivation of the PTHrP promoter. In coimmunoprecipitation assays, we find that Tax facilitates the interaction between Ets1 and Sp1, forming a ternary complex. When the Sp1 site in the PTHrP promoter was mutated, the Tax/Ets1 cooperative effect was dramatically decreased. This suggests that Sp1 plays an important role in the Ets1-dependent Tax transactivation of the PTHrP P2 promoter. Finally, we demonstrate that Gal4-Tax is a strong activator of the Gal PTHrP promoter, implying that Tax contributes directly to the transcriptional activation of the promoter. We propose a model in which the Tax/Ets1 cooperative effect on the PTHrP P2 promoter is based on the ability of Tax, Ets1, and Sp1 to form a ternary complex on the template DNA. Tax facilitates the interaction of Ets1/Sp1 and participates directly in the transcription initiation process.

Cerebral sparganosis: clinical manifestations, treatment, and outcome

Cerebral sparganosis is a rare parasitic disease caused by infestation by the plerocercoid larva of Spirometra mansoni. The authors retrospectively analyzed 17 cases of cerebral sparganosis treated at Seoul National University Hospital between 1986 and 1994. The patients' ages at diagnosis ranged from 6 to 57 years (median 32 years) and the male/female ratio was 13:4. Diagnosis was based on radiological findings, serological test results, operative findings, and histopathological examinations. Characteristic magnetic resonance (MR) findings consisted of widespread white matter degeneration and cortical atrophy, mixed-signal lesion (low in the central and high in the peripheral regions on T2-weighted images) with irregular dense enhancement of central foci and changes in the location and shape of the enhancing lesion in follow-up studies. Ten patients underwent surgical removal of the parasitic lesion, six received medical treatment alone (five with praziquantel and one with antiepileptic drugs), and one underwent insertion of a ventriculoperitoneal shunt and a course of praziquantel. Follow-up periods ranged from 13 to 111 months (mean 49 months). Seven patients who underwent complete removal of the lesion, live worm, or degenerative worm with surrounding granuloma showed a favorable course. Patients who received medical treatment alone or incomplete removal exhibited progression in their neurological deficits and their seizures could not be controlled. Medication with praziquantel seemed to have no killing effect on live worms. The authors conclude that MR imaging is the most valuable modality for the early detection of cerebral sparganosis and that complete surgical removal of granuloma together with worms, whether they are alive or degenerative, is the treatment of choice.

The IE2 regulatory protein of human cytomegalovirus induces expression of the human transforming growth factor beta1 gene through an Egr-1 binding site

Increases in transforming growth factor beta1 (TGF-beta1) mRNA and biological activity in the early phase of human cytomegalovirus (CMV) infection in fibroblasts are paralleled by increased TGF-beta1-chloramphenicol acetyltransferase (CAT) reporter gene activity. To determine how CMV infection transactivates the TGF-beta1 promoter, we examined the effects of the cotransfected IE2 regulatory protein of human CMV on 5'-deleted TGF-beta1 promoter-CAT reporter genes in transient DNA transfection assays. Two upstream TGF-beta1 promoter regions each containing an Egr-1 consensus site were shown to be important for IE2-induced transactivation in a cell type that displayed greatly reduced nonspecific activity. Furthermore, transfer of an Egr-l site from between positions -125 and -98, but not point mutant versions of this site, to a heterologous promoter also conveyed IE2 responsiveness. Addition of an IE2 expression vector or use of the U373 A45 astrocytoma cell line expressing IE2 also produced synergistic stimulation of GAL4-Egr-l-mediated activation of a target promoter containing GAL4 binding sites. The 80-kDa IE2 protein present in A45 cells proved to selectively bind to glutathione S-transferase (GST)-Egr-1 beads. The results of in vitro protein binding assays also revealed that an intact in vitro-translated IE2 protein bound directly to the GST-Egr-1 fusion protein through the zinc finger domain of the Egr-1 protein and that this binding activity was abolished by deletion of parts of the zinc finger DNA-binding domain. Similarly, the Egr-1 protein was found to associate preferentially with a small region within the C-terminal half of the IE2 protein adjacent to the DNA-binding and dimerization domains that are important for both transactivation and downregulation. We conclude from these observations that IE2 may regulate transcription of the TGF-beta1 gene as well as other potential cellular targets by virtue of its ability to interact with the Egr-1 DNA-binding protein.

Interaction of the human T-cell lymphotropic virus type 1 tax transactivator with transcription factor IIA

The Tax protein of human T-cell lymphotropic virus type 1 (HTLV-1) is a 40-kDa transcriptional activator which is critical for HTLV-1 gene regulation and virus-induced cellular transformation. Tax is localized to the DNA through its interaction with the site-specific activators cyclic AMP-responsive element-binding protein, NF-kappaB, and serum response factor. It has been suggested that the recruitment of Tax to the DNA positions Tax for interaction with the basal transcriptional machinery. On the basis of several independent assays, we now report a physical and functional interaction between Tax and the transcription factor, TFIIA. First, Tax was found to interact with the 35-kDa (alpha) subunit of TFIIA in the yeast two-hybrid interaction system. Importantly, two previously characterized mutants with point mutations in Tax, M32 (Y196A, K197S) and M41 (H287A, P288S), which were shown to be defective in Tax-activated transcription were unable to interact with TFIIA in this assay. Second, a glutathione-S-transferase (GST) affinity-binding assay showed that the interaction of holo-TFIIA with GST-Tax was 20-fold higher than that observed with either the GST-Tax M32 activation mutant or the GST control. Third, a coimmunoprecipitation assay showed that in HTLV-1-infected human T lymphocytes, Tax and TFIIA were associated. Finally, TFIIA facilitates Tax transactivation in vitro and in vivo. In vitro transcription studies showed reduced levels of Tax-activated transcription in cell extracts depleted of TFIIA. In addition, transfection of human T lymphocytes with TFIIA expression vectors enhanced Tax-activated transcription of an HTLV-1 long terminal repeat-chloramphenicol acetyltransferase reporter construct. Our study suggests that the interaction of Tax with the transcription factor TFIIA may play a role in Tax-mediated transcriptional activation.

Central neurocytoma: proliferative potential and biological behavior

The authors analyzed 13 central neurocytomas diagnosed at Seoul National University Hospital between January 1982 and December 1993 to clarify the proliferative potential and biological behavior of these tumors. The tumor was confined to the lateral and third ventricles in 12 cases and in one case extended from the posterior thalamus to the body and trigone area of the lateral ventricle. In all 13 cases, typical clinical and radiological findings were observed, and histological diagnosis was performed via craniotomy. The diagnosis was made using light microscopic examination, immunohistochemical staining for neuronal markers, and electron microscopic findings of neuronal differentiation. One patient died due to tumor progression with recurrence 26 months after subtotal removal plus radiation therapy. Another patient had a recurrence 18 months after total tumor removal. The remaining 11 patients are free of recurrent tumor after a follow-up period that ranged from 14 to 109 months (median 50 months). To predict the proliferative potential, immunoreactivity to proliferating cell nuclear antigen (PCNA), silver colloid staining for nucleolar organizing regions (AgNORs), and DNA flow cytometry were performed in 10 of the 13 cases. The proportion of PCNA-positive cells was less than 1% in all cases and the AgNORs score ranged from 1.11 to 2.0 (mean 1.67). The DNA flow cytometry revealed diploidy in all cases and the calculated proliferation index ranged from 5.1% to 9.6% (mean 7.8%). The one case of tumor recurrence, in which the authors performed the study of proliferative potential, and another case that demonstrated mild nuclear pleomorphism also showed low percentages of PCNA-positive cells, low AgNORs scores, and diploidy in DNA flow cytometry. It is suggested that most central neurocytomas follow a benign clinical course with low proliferative potential assessed by PCNA, AgNORs, and DNA flow cytometry; however, recurrence is possible within a relatively short time period.

Primary central nervous system lymphoma: variety of clinical manifestations and survival

A retrospective analysis of 23 non-immune compromised patients with primary central nervous system lymphoma (PCNSL) is reported. The patients consist of 14 males and 9 females and the median age is 50 years. Most patients presented with focal neurological deficits or symptoms of increased intracranial pressure (ICP) due to mass effects around the periventricular area. However, there were four cases of diffuse type, one case of intramedullary tumour, and four cases with rapid disease progression. All the patients underwent histological confirmation by craniotomy (16 cases) or stereotactic biopsy (7 cases). The radiation therapy started after histological diagnosis in all and 6 cases received additional chemotherapy. The median survival after diagnosis of overall patients was 23 months. Six patients are in disease free status at a mean of 35 months follow-up. The uni- and multi-variative risk analysis revealed five favourable factors on survival: (1) age less than 60 years (0.05 < p < 0.1); (2)pre-operative Karnofsky performance scale (KPS) > or = 70 (p < 0.05); (3) symptom duration over four weeks (p < 0.05); (4) radiation dosage > or = 5500 cGy (p < 0.05); (5)absence of malignant cells in cerebrospinal fluid (CSF) (p < 0.05). The most frequent site of recurrence was the local area as shown in seven cases out of 11 recurrent cases. But six patients had diffuse recurrence (4 cases), systemic recurrence (2 cases), and drop metastasis (1 case). Although the recurred PCNSL had rapid progression and a grave prognosis, aggressive treatment prolonged the postrecurrence survival time significantly. Our experience suggests that 1) there are various clinical and radiological presentations and progressions of the disease; 2) treatment method should be decided along with the clinical presentation, progression of disease, and prognostic factors; 3) early diagnosis and early detection of recurrence enable the start of definitive treatment when the medical condition is still satisfactory.

Loss of heterozygosity on chromosome 10, 13q(Rb), 17p, and p53 gene mutations in human brain gliomas

Using the methods of restriction fragment length polymorphism (RFLP) and single strand conformation polymorphism (SSCP) analyses, we have examined 33 cases of human gliomas with various malignant grades to detect the deletions of putative tumor suppressor gene loci, chromosome 10, 13q(retinoblastoma gene, Rb), 17p, and p53 mutation. We observed loss of heterozygosity (LOH) at loci on chromosome 10 (36%), 13q(Rb) (54%), and 17p(50%) in malignant gliomas. There, however was no allelic loss on chromosome 10 and 17p in low-grade gliomas. Rb gene deletions were seen in low-grade gliomas, including oligodendroglioma and ependymoma. This finding suggests that Rb inactivation may be an early genetic event in the development and progression of gliomas. We correlated the results of LOH on chromosome 17p and p53 mutation. Among the 8 cases which showed LOH on chromosome 17p, only three cases (38%) revealed p53 mutations. Low incidence of p53 mutations in cases with chromosome 17p deletions suggests that some other tumor suppressor genes may be located on chromosome 17p.

99mTc-HMPAO labeled leukocyte SPECT in intracranial lesions

BACKGROUND

Scintigraphy with 111In (indium-111)-oxine or 99mTechnetium-hexamethylpropyleneamine oxime (99mTc-HMPAO) labeled leukocytes has been used to differentiate brain abscess from brain tumor. However, there are false positive or false negative results from planar scintigraphic images. So a more specific and sensitive scintigraphic technique needs to be developed.

METHODS

Planar and single photon emission computed tomography (SPECT) images were obtained and reviewed in 14 patients with intracerebral ring-enhancing lesions on computed tomography (CT) or magnetic resonance imaging (MRI). In all patients, diagnosis was confirmed by histopathologic examination. The effect of steroids or antibiotics on scintigraphic finding was examined.

RESULTS

Abscess was confirmed in six patients, tumor in six, tuberculoma and cysticercosis in one each, respectively. In all the patients with abscess, SPECT showed increased focal activity irrespective of steroid or antibiotic therapy. Increased radioactivity, which could not be detected on planar images, could be identified in two patients with abscess. In three of the six patients with tumor, radiolabeled leukocytes did not accumulate in the tumor. In the other three patients with tumor, SPECT showed focally increased activity that was less intense than the activity shown in the patients with abscess.

CONCLUSIONS

99mTc-HMPAO labeled leukocyte SPECT is useful for the differential diagnosis of intracerebral ring-enhancing lesions, and the use of steroids or antibiotics does not influence the sensitivity of SPECT. Diagnostic sensitivity of scintigraphy with labeled leukocytes could be improved by SPECT in addition to planar image.

The retinoblastoma gene product negatively regulates transcriptional activation mediated by the human cytomegalovirus IE2 protein

The IE2 gene product of human cytomegalovirus (HCMV) is one of a few viral regulatory proteins expressed immediately upon infection of the host cell. It is a potent transcriptional activator of many viral and cellular promoters. We found that the retinoblastoma susceptibility gene product (Rb) dramatically suppressed this IE2 transactivation of various promoters. However, unlike another tumor suppressor protein, p53, Rb did not have any significant effect on basal levels of transcription, suggesting that Rb specifically interacts with IE2 rather than other cellular factors involved in the general transcription machinery. We found by protein-affinity chromatography that Rb in nuclear extracts or produced by in vitro translation directly bound to IE2. Our results suggest that Rb may regulate the life cycle of HCMV, which is endemic in the human population. Furthermore, these data may provide new insights into the slow rate of HCMV DNA replication in cells and the possible involvement of HCMV in tumorigenesis.

Chemical modification of implantable biologic tissue for anti-calcification

Biologic porcine tissue was modified by coupling sulfonated polyethyl-eneoxide (PEO-SO3) and the effect of modification on calcification was evaluated in vitro and in vivo. The modification process involves grafting PEO-SO3 to porcine valve leaflet either by carbodiimide (EDC) activation or by direct coupling using glutaraldehyde. Thermal property, measured by differential scanning calorimetry, showed that the shrinkage temperature of modified tissue increased compared with control tissue and fresh tissue, suggesting increased thermal stability. Resistance to collagenase digestion revealed that modified tissues have greater resistance to enzyme digestion than do control tissues. In vitro calcification showed that modified tissues have less calcium deposition than do control tissues. In vivo calcification, using a rat subcutaneous implantation model, also showed less calcification of modified tissue than that of control. The resistance of modified tissue to collagenase, higher shrinkage temperature, and reduced calcification, when compared with control tissue, attest to the usefulness of this chemical modification for implantable biologic tissue.

Diastematomyelia--clinical manifestation and treatment outcome

Diastematomyelia is a rare congenital anomaly characterized by a division of the spinal cord or the filum terminale into two parts. In Korea, only one case has been reported. The authors have operated on 5 cases of diastematomyelia with septum since July, 1978. The ages ranged from 1 to 44 years (median; 11 years). There were 2 boys, 2 girls and an adult man. The disease manifested by cutaneous abnormalities and neurological or orthopedic deficits. Pain was a chief complaint in the adult patient. The symptoms had progressed in 3 cases. The diagnosis was made correctly by CT myelography or MRI in 4 cases. The median septum was located at the lumbar area in 4 cases and at the lumbosacral region in 1 case. Associated abnormalities included low lying conus (5 cases), lipoma (2 cases), thickened filum terminale (1 case), hemilipomyelomeningocele (1 case) and syrinx (1 case). The median septum was removed. The dural sleeve adjoining the septum was resected and the dural sac was reconstructed. The role of MRI in the diagnosis and planning of surgery and the high frequency of associated low lying conus were emphasized. Though the surgical treatment relieved pain, it did not reverse the neurological deficits or orthopedic deformities significantly, which suggests the beneficial effects of early surgical intervention in the cases with progressive symptoms.

Instantaneous Reproductive Effort in Female American Oysters, Crassostrea virginica, Measured by a New Immunoprecipitation Assay

An immunoprecipitation assay was developed for measuring instantaneous reproductive effort in female American oysters, Crassostrea virginica. Oysters were injected with 14C-leucine and incubated in situ for 1 to 30 h periodically throughout the annual gametogenic cycle. Gonadal protein labeled with 14C-leucine was precipitated from an oyster homogenate with rabbit anti-oyster egg IgG as the primary antibody. Antibody-oyster egg protein complex was further purified by immunoadsorption with staphylococcal protein A cell suspension. The quantity of oyster eggs was determined by single-ring immunodiffusion. A mathematical model was developed to calculate the instantaneous reproductive rate of oysters and to estimate the number of days required from the initiation of gonadal development to spawning. The oyster population was lightly to moderately infected with a protozoan parasite, Perkinsus marinus. A negative correlation between the intensity of infection and the rate of gonadal production suggests that P. marinus retards the rate of gamete development. The seasonal cycle of gamete production determined by direct measurements of egg protein production was not equivalent to that determined by standard gonadal-somatic index (GSI), except at the most basic level. GSI was highest during the spring spawning peak, but the rate of gamete production was highest in the fall. Accordingly, the two measurements, rate versus standing crop (volume of gonad), reveal a substantially different picture about the details of the spawning season. Estimates of the time required to reach spawning condition ranged from several weeks to 1 or 2 months; these values agree with published estimates derived from less direct methods. Direct rate measurements thus seem to accurately reflect the true rate at which gametic tissue is produced in the field. A positive correlation between oyster size and the estimated days to spawn suggests that larger oysters require longer to prepare to spawn. Furthermore, the range in observed somatic and gametic growth emphasizes the conservatism of somatic growth and the volatility of gonadal growth that is borne out by the results of population dynamics models of oysters.

Bacterial expression, purification of full length and carboxyl terminal fragment of Alzheimer amyloid precursor protein and their proteolytic processing by thrombin

Human amyloid protein precursor(APP770) and its carboxyl terminal portion (CT105) including beta/A4 domain were highly expressed using strong expression systems in E. coli. These recombinant APP peptides were purified with a combination of urea solubilization and ion-exchange chromatography and used for proteolytic processing by thrombin. Three thrombin cleavage sites were predicted by the decrease of APP770 and the appearance of M(r) 56, 27 and 18 kDa fragments containing beta/A4 domain on SDS-PAGE gel and on the immunoblot. A similar but limited proteolysis of platelet APPs exposed to thrombin resulted in the stimulated production of 60 and 27 KDa carboxyl terminal peptides containing the intact beta/A4. This thrombin mediated proteolysis was completely blocked by hirudin, the specific thrombin inhibitor. These results suggest that thrombin may play a role in altered processing of APP to generate potentially amyloidogenic intermediates in vivo leading to amyloid deposition.

Histopathological changes of the cat brain in experimental sparganosis

Histopathological changes of the brain were observed in 22 mongrel cats each of which was subjected to intracranial inoculation of 3 or 5 plerocercoids of Spirometra erinacei. The brains were examined at 2 weeks, 1, 3, and 6 months post-inoculation (PI). Grossly, the brain lesion consisted of a mass of worm capsule and/or hemorrhagic tract. Microscopically hypertrophied astrocytes, lymphocytes, plasma cells, RBCs, polymorphonuclear leukocytes, and hemosiderin laden macrophages were found around the worms or tracts in all groups. The number of reactive astrocytes increased mainly in the white matter. In the lesions 3 months PI, the sectioned worms were encircled with fibrous tissue along with numerous RBCs, inflammatory cells, and necrotic debris. Collagenous fibers were also demonstrated. Outside the inflammation, a wide edematous zone developed and numerous neuroglial fibers were also found. The location of the worms or the tracts was random in the brain lobes, but the worm seemed to migrate mainly along the white matter.

Cerebral aspergillosis in immunologically competent patients

Aspergillosis of the central nervous system is a rare disease, especially if the patient's immune system is not compromised. The authors report three cases of cerebral aspergillosis in the immunocompetent state: a rhinocerebral form in a diabetic patient, a direct extension from chronic Aspergillus otitis media, and a postoperative Aspergillus brain abscess after brain tumor surgery. In spite of the poor prognosis of cerebral aspergillosis, two of the patients survived. The pathogenesis, predisposing factors, radiologic findings including magnetic resonance image, and the outcome are presented. The pertinent literature of cerebral aspergillosis is also reviewed.

Intracranial mesenchymal chondrosarcoma: a case report and literature review

Intracranial mesenchymal chondrosarcoma is a rare entity. The case of a 13-year-old girl with mesenchymal chondrosarcoma which seemed to arise from the dura mater is presented here together with a review of the literature. In the present case, the tumor involved the superior sagittal sinus. It recurred 21 months after gross total removal of the mass and coagulation of the involved wall of the superior sagittal sinus. Reoperation was performed followed by radiation therapy.

MRI of intracranial subependymoma: report of a case

Subependymoma is a rare, benign intraventricular tumour and a case of septum pellucidum origin examined with CT and MR is reported. Well demarcated non-enhancing mass with multiple small intratumoral cysts is demonstrated on CT and MR images. The differential diagnosis from ependymoma has some therapeutic implications but may not be possible by CT or MRI.

Compartmental analysis of RBC circulation through the rabbit kidney

This experiment involved 12 rabbits of both sexes, weighing 2.1 kg. After anesthesia, the kidneys were exposed, isolated and cannulated in the renal artery, ureter and sometimes in the vein as well. The kidney were perfused through the renal artery with Krebs-Henseleit solution, which were then filtered to be free of particles, gased with 95% O2-5% CO2, and kept at 37 degrees C. We measured RBCs concentrations by means of Coulter Counter in the venous outflow collected, and plotted them against the volume perfused. Using 2 different flow rates, 9 ml/min (group I) and 19 ml/min (group II), we found that the RBCs decreased in a multiexponential decay fashion and a biophysical model for each flow rate was constructed. These models indicated that there were more cell stores (2.20 x 10(10)) in the fast compartment of group II than in group I (1.72 x 10(10)). This difference is not statistically significant, but certainly coincides with urine flow collected from ureter cannula during perfusion. Our present data clearly suggest that in order to clear 99% blood cells out of 10-12 gm rabbit kidneys, at least 3-6 ml of cell free perfusate is required while clearing the whole blood cells out of human kidneys (200-240 gm) may need 600 ml or more. Thus, we recommend that at least 600 ml of perfusate should be used to clear most of the blood cells in the renal vasculature before renal transplantation is performed.

Effects of site-directed mutations on processing and activities of penicillin G acylase from Escherichia coli ATCC 11105

Penicillin G acylase from Escherichia coli ATCC 11105 is synthesized from its precursor polypeptide into a catalytically active heterodimer via a complex posttranslational processing pathway. Substitutions in the pair of aminoacyl residues at the cleavage site for processing the small and large subunits were made. Their processing phenotypes and penicillin G acylase activities were analyzed. By the introduction of a prolyl residue at either position, the processing of the small subunit was blocked without a change in enzymatic activity. Four other substitutions had no effect. At the site for processing the large subunit, four substitutions out of the seven examined blocked processing. In general, penicillin G acylase activity seemed to be proportional to the efficiency of the large-subunit-processing step. Ser-290 is an amino acid critical for processing and also for the enzymatic activity of penicillin G acylase. In the mutant pAATC, in which Ser-290 is mutated to Cys, the precursor is processed, but there is no detectable enzymatic activity. This suggests that there is a difference in the structural requirements for the processing pathway and for enzymatic activity. Recombination analysis of several mutants demonstrated that the small subunit can be processed only when the large subunit is processed first. Some site-directed mutants from which signal peptides were removed showed partial processing phenotypes and reduced enzymatic activities. Their expression showed that the prerequisite for penicillin G acylase activity is the efficient processing of the large subunit and that the maturation of the small subunit does not affect the enzymatic activity.

Intraventricular neurocytoma: clinicopathological analysis of seven cases

A retrospective analysis of seven patients with intraventricular neurocytoma is presented. Patient age at diagnosis ranged from 15 to 38 years (mean 24.6 years) and the male:female ratio was 6:1. Raised intracranial pressure due to hydrocephalus was the main cause of the clinical manifestations. An isodense mass with multiple intratumoral cysts and homogeneous contrast enhancement was the characteristic computerized tomography finding. The lesions commonly involved the lateral ventricle with or without extension to the third ventricle. Cerebral angiography showed homogeneous vascular staining in five patients. Magnetic resonance images revealed a mass isointense with the cerebral cortex on both T1- and T2-weighted images. Gadolinium-diethylenetriaminepenta-acetic acid-enhanced images showed homogeneous enhancement. Total removal of the tumor was possible in four patients. Pathologically, six cases were initially diagnosed as oligodendroglioma and the remaining case as ependymoma. However, immunohistochemical studies demonstrated strong positivity for neuron-specific enolase in all seven cases and for synaptophysin in five cases. On electron microscopy, three cases showed well-defined neurosecretory granules and 10-nm microtubules in their cytoplasm and cytoplasmic processes. One patient developed a recurrent tumor 18 months after surgery. The remaining six patients are free of recurrent tumors at 2 to 62 months after surgery. It is suggested that neurocytoma must be included in the differential diagnosis of intraventricular lesions, and that electron microscopic and immunohistochemical studies should be undertaken.