Snapshots of catalysis: the structure of fructose-1,6-(bis)phosphate aldolase covalently bound to the substrate dihydroxyacetone phosphate

Fructose-1,6-bis(phosphate) aldolase is an essential glycolytic enzyme found in all vertebrates and higher plants that catalyzes the cleavage of fructose 1,6-bis(phosphate) (Fru-1,6-P(2)) to glyceraldehyde 3-phosphate and dihydroxyacetone phosphate (DHAP). Mutations in the aldolase genes in humans cause hemolytic anemia and hereditary fructose intolerance. The structure of the aldolase-DHAP Schiff base has been determined by X-ray crystallography to 2.6 A resolution (R(cryst) = 0.213, R(free) = 0.249) by trapping the catalytic intermediate with NaBH(4) in the presence of Fru-1,6-P(2). This is the first structure of a trapped covalent intermediate for this essential glycolytic enzyme. The structure allows the elucidation of a comprehensive catalytic mechanism and identification of a conserved chemical motif in Schiff-base aldolases. The position of the bound DHAP relative to Asp33 is consistent with a role for Asp33 in deprotonation of the C4-hydroxyl leading to C-C bond cleavage. The methyl side chain of Ala31 is positioned directly opposite the C3-hydroxyl, sterically favoring the S-configuration of the substrate at this carbon. The "trigger" residue Arg303, which binds the substrate C6-phosphate group, is a ligand to the phosphate group of DHAP. The observed movement of the ligand between substrate and product phosphates may provide a structural link between the substrate cleavage and the conformational change in the C-terminus associated with product release. The position of Glu187 in relation to the DHAP Schiff base is consistent with a role for the residue in protonation of the hydroxyl group of the carbinolamine in the dehydration step, catalyzing Schiff-base formation. The overlay of the aldolase-DHAP structure with that of the covalent enzyme-dihydroxyacetone structure of the mechanistically similar transaldolase and KDPG aldolase allows the identification of a conserved Lys-Glu dyad involved in Schiff-base formation and breakdown. The overlay highlights the fact that Lys146 in aldolase is replaced in transaldolase with Asn35. The substitution in transaldolase stabilizes the enamine intermediate required for the attack of the second aldose substrate, changing the chemistry from aldolase to transaldolase.

Amphiphysin IIb-1, a novel splicing variant of amphiphysin II, regulates p73beta function through protein-protein interactions

p73 is a nuclear protein that is similar in structure and function to p53. Notably, the C-terminal region of p73 has a regulatory function, through interactions with a positive or negative regulator. In this study, we use the yeast two-hybrid technique to identify a novel p73beta binding protein, designated amphiphysin IIb-1. Amphiphysin IIb-1 is one of the splicing variants of amphiphysin II, and has a shorter protein product than amphiphysin IIb, which has been previously reported. We confirmed that amphiphysin IIb-1 binds full-length p73beta, both in vitro and in vivo. This association is mediated via the SH3 domain of amphiphysin IIb-1 and C-terminal amino acids 321-376 of p73beta. Double immunofluorescence patterns revealed that p73beta is relocalized to the cytoplasm in the presence of amphiphysin IIb-1. Overexpression of amphiphysin IIb-1 was found to significantly inhibit the transcriptional activity of p73beta in a dose-dependent manner. In addition, the cell death function of p73beta was inhibited by amphiphysin IIb-1. These findings offer a new insight into the regulation mechanism of p73beta, and suggest that amphiphysin IIb-1 modulates p73beta function by direct binding.

Inducible RGS2 is a cross-talk regulator for parathyroid hormone signaling in rat osteoblast-like UMR106 cells

Parathyroid hormone (PTH) activates dual signal transduction systems via Galphas and Galphaq proteins. We now report a novel mechanism by which "cross-talk" may occur between the Galphas and Galphaq signaling pathways. RGS2 (Regulator of G protein Signaling 2) mRNA was rapidly and transiently increased only by PTH analogs (PTH1-84, 1-34, 1-31, and PTHrP) that activated the Galphas-mediated cAMP/PKA signaling pathway, whereas activation of the Galphaq-mediated Ca(2+)/PKC signaling pathway by PTH3-34 had no effect on RGS2 expression. Treatment of UMR106 cells with nonPTH activators of the cAMP/PKA signaling pathway such as cholera toxin, forskolin, 8-Br-cAMP, and dibutyryl-cAMP also significantly elevated RGS2 mRNA levels, while activator of the Galphaq pathway PMA did not. Pretreatment using the Galphas signaling pathway inhibitors SQ22536 and H89 significantly blocked PTH-induced RGS2 expression, but the Galphaq signaling pathway inhibitor bisindolylmaleimide I had no effect. Therefore, RGS2 expression is governed solely by the Galphas signaling pathway. Additionally, we demonstrate for the first time that RGS2 binds to both Galphas and Galphaq subunits in their transition state (GDP/AlF(-4)-bound) forms, suggesting that RGS2 has the potential to act as a bridge between the cAMP/PKA and Ca(2+)/PKC pathways, and that it may act as a cross-talk regulator for these two PTH signaling pathways.

Bax-dependent apoptosis induced by ceramide in HL-60 cells

Ceramide is an important lipid messenger involved in mediating a variety of cell functions including apoptosis. In this study, we show that antisense bax inhibits cytochrome c release, poly(ADP-ribose)polymerase cleavage and cell death induced by ceramide in HL-60 cells. In addition, ceramide induces translocation of Bax to mitochondria. The addition of the broad spectrum caspase inhibitor zVAD-fmk prevented ceramide-induced apoptotic cell death but did not inhibit translocation of Bax and mitochondrial cytochrome c release. Furthermore, ceramide inhibits the expression of the antiapoptotic protein Bcl-xL with an increase in the ratio of Bax to Bcl-xL. These data provide direct evidence that Bax plays an important role in regulating ceramide-induced apoptosis.

Intrathoracic malignant peripheral nerve sheath tumor in von Recklinghausen's disease

Malignant peripheral nerve sheath tumor (MPNST) is defined as any malignant tumor arising from or differentiating toward the cells of the peripheral nerve sheath. MPNST accounts for about 5-10% of all soft tissue tumors and is often associated with neurofibromatosis type I (NF-1, von Recklinghausen's disease). It is one of the malignant tumors associated with von Recklinghausen's disease. Its common site is the lower and upper extremities, trunk, head and neck. But intrathoracic manifestations are very rare. We report a case of a 40 year-old man with multiple neurofibromatosis who was presented with an intrathoracic malignant peripheral nerve sheath tumor.

Caspase-3-mediated cleavage of the NF-kappa B subunit p65 at the NH2 terminus potentiates naphthoquinone analog-induced apoptosis

The transcription factor nuclear factor kappaB (NF-kappaB) plays a crucial role in immune and inflammatory response, and protects cells from apoptosis. In this report, we investigate whether the NF-kappaB signaling pathway is blocked during apoptosis induced by 2,3-dichloro-5,8-dihydroxy-1,4-naphthoquinone (NA), an analog of naphthoquinone. It is observed that NA triggers apoptotic cell death in HeLa cells and destroys resistance to apoptosis caused by tumor necrosis factor-alpha. Data presented in this study establish that p65/RelA, a subunit of NF-kappaB, is cleaved at Asp(97) by caspase-3 during apoptosis. Caspase-3-cleaved p65 loses transcriptional activity and potentiates NA-induced apoptosis, in contrast to an uncleavable mutant of p65, which protects the cell from apoptosis. Caspase-3, which is responsible for the cleavage of p65, is activated via the cytochrome c/caspase-9 signaling pathway rather than Fas/caspase-8 pathway during NA-induced apoptosis. Our results suggest that NA induces apoptosis by the negative regulation of cell survival through caspase-3-mediated cleavage of p65.

Dextromethorphan affects cocaine-mediated behavioral pattern in parallel with a long-lasting Fos-related antigen-immunoreactivity

In order to understand the underlying mechanisms responsible for the behaviors mediated by dextromethorphan (DM), we examined the effects of DM on locomotor activity and locomotor patterns in mice, and Fos-related antigen immunoreactivity (FRA-IR) of mouse brain following repeated administration of cocaine. Combined treatments (30 min prior to each cocaine administration) with DM dose-dependently decreased locomotor activity for high doses of cocaine (20 mg/kg, i.p./day x 7). DM combinations did not significantly affect hyperactivity for 10 mg cocaine/kg, i.p./day x 7. In contrast, combined treatments with DM increased the locomotor activity for 5 mg cocaine/kg, i.p./day x 7. These results were consistent with alterations in marginal activity. Repeated administration with cocaine or DM increased FRA-IR in the nucleus accumbens (NAc) and striatum which lasted for at least 7 days. Our results suggest that DM exhibits biphasic effects on the locomotor stimulation induced by cocaine, and that locomotor activities are in parallel with FRA-IR of the striatal complex. However, the role of FRA-IR regulated by DM or/and cocaine remains to be further determined.

Gene polymorphisms of endothelial nitric oxide synthase and angiotensin-converting enzyme in patients with lung cancer

The objectives of this study were to examine the possible involvement of endothelial nitric oxide synthase (ecNOS) and angiotensin-converting enzyme (ACE) genes in the genetic basis of lung cancer. Two hundred eighteen patients with lung cancer and 121 healthy subjects were included in this study. The ecNOS and ACE genotypes were determined in all subjects by polymerase chain reaction. The distribution of genotypes of ecNOS gene was significantly different in the lung cancer group than in the control population. ACE genotype distribution was not significantly different in the lung cancer group compared with the control group. These results suggest that polymorphisms of the ecNOS gene, but not the ACE gene, may be associated with the development of lung cancer.

UVB-induced GM-CSF production is suppressed by dexamethasone in HaCaT cells

BACKGROUND

Epidermal keratinocytes are important sources of a wide variety of cytokines that include the Granulocyte-macrophage Colony Stimulating Factor (GM-CSF). Glucocorticoids have been shown to inhibit the production of several cytokines. However, their effect on GM-CSF synthesis by keratinocytes is still unknown.

METHODS

The effects of glucocorticoid on GM-CSF production by keratinocytes were evaluated using ELISA and RT-PCR analysis.

RESULTS

GM-CSF secretion by HaCaT cells increased with increasing UVB exposure. Dexamethasone suppressed basal release of GM-CSE In addition, it strongly inhibited both the UVB-mediated augmentation of GM-CSF protein production and mRNA expression. Lincomycin enhanced slightly the inhibitory effect of dexamethasone on GM-CSF synthesis, while lincomycin itself had no effect on GM-CSF secretion.

CONCLUSION

Results showed that dexamethasone suppressed basal release and UVB-induced production of GM-CSF by keratinocytes.

National trends in condom use among at-risk heterosexuals in the united states

Based on national level surveys, we examined data relevant to the United States' overall effort to prevent the spread of HIV among heterosexual adults. We examined changes in condom use among at-risk heterosexuals over the past decade. The observed increases over time in condom use across all heterosexual at-risk population segments are consistent with the observed (declines) trends in HIV and syphilis in the 1990s. These results and findings from prior studies suggest that U.S. efforts to facilitate condom use and contain HIV and related sexually transmitted disease (STD)-cofactors among adult at risk heterosexuals was succeeding over most of the 1990s. The absence of national level behavioral trend data after 1996, and the ambiguities of HIV spread suggest some caution in projecting trends into this century. National and local efforts need to be directed at sustaining behavioral change and conducting more rigorous studies on population trends in HIV/STD-related behaviors/pathogens.

The continuing HIV epidemic among men who have sex with men

OBJECTIVES

This study characterized the AIDS epidemic among urban men who have sex with men (MSM).

METHODS

A probability sample of MSM was obtained in 1997 (n = 2881; 18 years and older) from New York, Los Angeles, Chicago, and San Francisco, and HIV status was determined through self-report and biological measures.

RESULTS

HIV prevalence was 17% (95% confidence interval = 15%, 19%) overall, with extremely high levels in African Americans (29%), MSM who used injection drugs (40%), "ultraheavy" noninjection drug users (32%), and less educated men (< high school, 37%). City-level HIV differences were non-significant once these other factors were controlled for. In comparing the present findings with historical data based on public records and modeling, HIV prevalence appears to have declined as a result of high mortality (69%) and stable, but high, incidence rates (1%-2%).

CONCLUSIONS

Although the findings suggest that HIV prevalence has declined significantly from the mid-1980s, current levels among urban MSM in the United States approximate those of sub-Saharan countries (e.g., 14%-25%) and are extremely high in many population subsegments. Despite years of progress, the AIDS epidemic continues unabated among subsegments of the MSM community.

Acute eosinophilic pneumonia associated with amitriptyline in a hemodialysis patient

Drugs are well known causes of eosinophilic lung disease. In many patients, drug-induced eosinophilic lung disease presents with transient eosinophilic infiltrates that disappear after discontinuation of the drug. Some patients, however, experience a fulminant, acute eosinophilia-like disease. Recently, we experienced a case of amitriptyline-associated acute eosinophilic pneumonia with respiratory failure in a diabetic hemodialysis patient. Eight days after treatment with amitriptyline, sudden fever, chill, dry cough and dyspnea developed. Subsequently, multiple patch consolidations appeared on the chest radiographs. Bronchoalveolar lavage (BAL), established a diagnosis of acute eosinophilic pneumonia. After immediate discontinuation of amitriptyline, a rapid clinical and radiological improvement was observed. The present case indicates that the possibility of acute eosinophilic pneumonia should be fully considered in dialysis patients developing unexplained respiratory symptoms while on amitriptyline therapy.

Fas-independent apoptosis induced by UVC in p53-mutated human epithelial tumor A431 cells through activation of caspase-8 and JNK/SAPK

A431 cells/UVC-induced apoptosis/Caspase 8/Fas/JNK/PAPK. We previously observed that p53-mutated human epithelial tumor A431 cells underwent apoptosis after ultraviolet C (UVC) irradiation through the caspases-8 and -3 pathway. Fas/FasL is known to initiate apoptosis in several cell lines via caspase-8 activation. Then, to determine if Fas/FasL mediates apoptosis in A431. we investigated Fas expression and modulation in UVC-irradiated A431 cells. A431 constitutively expressed Fas, which gradually decreased after UVC-irradiation. Pretreatment with a neutralizing anti-Fas antibody, ZB4, did not abrogate the UVC-induced apoptosis. An agonistic anti-Fas antibody, CH11, very slowly induced apoptosis in A431. suggesting that the constitutively expressed Fas had a low functional potential. Hence, UVC-induced apoptosis in A431 seems to occur independent of the Fas signal. Interestingly, however, a pretreatment with CH11 remarkably potentiated UVC-induced apoptosis. An inhibitor of caspase-8, Ac-IETD-CHO, partially inhibited UVC-induced apoptosis. JNK was phosphorylated immediately after exposure to UVC. prior to apoptotic chromatin condensation. Our data suggest that the activation of caspase-8 occurs independent of Fas upregulation, and that JNK/ SAPK contributes to UVC-induced apoptosis in human epithelial A431 cells.

Genetic analyses of Acanthamoeba isolates from contact lens storage cases of students in Seoul, Korea

We conducted both the small subunit ribosomal DNA (SSU rDNA) polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and mitochondrial (mt) DNA RFLP analyses for a genetic characterization of Acanthamoeba isolates from contact lens storage cases of students in Seoul, Korea. Twenty-three strains of Acanthamoeba from the American Type Culture Collection and twelve clinical isolates from Korean patients were used as reference strains. Thirty-nine isolates from contact lens storage cases were classified into seven types (KA/LS1, KA/LS2, KA/LS4, KA/LS5, KA/LS7, KA/LS18, KA/LS31). Four types (KA/LS1, KA/LS2, KA/LS5, KA/LS18) including 33 isolates were regarded as A. castellanii complex by riboprints. KA/LS1 type was the most predominant (51.3%) in the present survey area, followed by KA/LS2 (20.9%), and KA/LS5 (7.7%) types. Amoebae of KA/LS1 type had the same mtDNA RFLP and riboprint patterns as KA/E2 and KA/E12 strains, clinical isolates from Korean keratitis patients. Amoebae of KA/LS2 type had the identical mtDNA RFLP patterns with A. castellanii Ma strain, a corneal isolate from an American patient as amoebae of KA/LS5 type, with KA/E3 and KA/E8 strains from other Korean keratitis patients. Amoebae of KA/LS18 type had identical patterns with JAC/E1, an ocular isolate from a Japanese patient. Three types, which remain unidentified at species level, were not corresponded with any clinical isolate in their mtDNA RFLP and riboprint patterns. Out of 39 isolates analyzed in this study, mtDNA RFLP and riboprint patterns of 33 isolates (84.6%) were identical to already known clinical isolates, and therefore, they may be regarded as potentially keratopathogenic. These results suggest that contact lens wearers in Seoul should pay more attention to hygienic maintenance of contact lens storage cases for the prevention of Acanthamoeba keratitis.

beta-Cell dysfunction rather than insulin resistance is the main contributing factor for the development of postrenal transplantation diabetes mellitus

BACKGROUND

Our study was undertaken to investigate the pathogenesis and possible risk factors for postrenal transplantation diabetes mellitus (PTDM).

METHODS

We recruited 114 patients with normal glucose tolerance (NGT) and performed both 75-g oral glucose tolerance tests (OGTT) and short insulin tolerance tests 1 week before and 9-12 months after transplantation.

RESULTS

The subjects were classified into three groups by World Health Organization criteria on the basis of OGTT after transplantation: (a) 36 (31.6%) subjects with normal glucose tolerance; (b) 51 (45.7%) subjects with impaired glucose tolerance (IGT); and (c) 27 (23.7%) subjects with postrenal transplantation diabetes mellitus. Dosages of steroid and cyclosporine were equivalent among the three groups. Before transplantation, the fasting and 2-hr plasma glucose and proinsulin/insulin (PI/I) ratios were significantly higher in the IGT and PTDM groups than in the NGT group, but the insulin sensitivity index (ISI) was not significantly different among the three groups. In addition, the area under the curve-insulin on OGTT was significantly lower in the PTDM group than in the NGT group. After transplantation, however, the ISI was increased in all groups. Furthermore, the ISI and PI/I ratios revealed significantly higher values in the PTDM group than in the NGT group after transplantation.

CONCLUSIONS

These results revealed that fasting and 2-hr plasma glucose levels, as well as the proinsulin/insulin ratio before transplantation, are both possible indicators of beta-cell dysfunction and may be predictors for the development of PTDM. Furthermore, beta-cell dysfunction, rather than insulin resistance, was proven to be the main factor for the pathogenesis of PTDM.

Positive and negative life events after counselling and testing: the Voluntary HIV-1 Counselling and Testing Efficacy Study

INTRODUCTION

The results of the Voluntary HIV-1 Counselling and Testing Efficacy Study support the efficacy and cost-effectiveness of HIV voluntary counselling and testing (VCT) for reducing risk behaviors in three developing countries.

METHODS

This report explores the social consequences of HIV VCT by examining the incidence of positive and negative life events at the first follow-up (an average of 7.3 months after recruitment). The incidence of positive and negative life events was compared between: (i) those who were randomly assigned to HIV VCT versus health information (HI); (ii) those who tested seronegative and those who tested seropositive; and (iii) those who disclosed their serostatus and those who did not.

RESULTS

The occurrence of most negative life events was rare (0--4%); positive life events were more common (17--39%). With few exceptions, those assigned to HIV VCT were no more likely to experience negative life events than those who were assigned to HI. For individuals, positive serostatus was associated with increased support from health professionals, the break-up of a marriage and being neglected or disowned by their family. Serodiscordant couples with an HIV-positive woman were most likely to report the break-up of a marriage (20 versus 0--7% for other groups) and the break-up of a sexual relationship (45 versus 22--38% for other groups). Disclosure was associated with strengthening of a sexual relationship except for HIV-seropositive women.

CONCLUSION

These findings, in combination with findings supporting the efficacy and cost-effectiveness of HIV VCT, support the dissemination of HIV VCT with appropriate support services in developing countries.

Response of Bacillus subtilis to cerulenin and acquisition of resistance

Cerulenin is a fungal mycotoxin that potently inhibits fatty acid synthesis by covalent modification of the active site thiol of the chain-elongation subtypes of beta-ketoacyl-acyl carrier protein (ACP) synthases. The Bacillus subtilis fabF (yjaY) gene (fabF(b)) encodes an enzyme that catalyzes the condensation of malonyl-ACP with acyl-ACP to extend the growing acyl chain by two carbons. There were two mechanisms by which B. subtilis adapted to exposure to this antibiotic. First, reporter gene analysis demonstrated that transcription of the operon containing the fabF gene increased eightfold in response to a cerulenin challenge. This response was selective for the inhibition of fatty acid synthesis, since triclosan, an inhibitor of enoyl-ACP reductase, triggered an increase in fabF reporter gene expression while nalidixic acid did not. Second, spontaneous mutants arose that exhibited a 10-fold increase in the MIC of cerulenin. The mutation mapped at the B. subtilis fabF locus, and sequence analysis of the mutant fabF allele showed that a single base change resulted in the synthesis of FabF(b)[I108F]. The purified FabF(b) and FabF(b)[I108F] proteins had similar specific activities with myristoyl-ACP as the substrate. FabF(b) exhibited a 50% inhibitory concentration (IC(50)) of cerulenin of 0.1 microM, whereas the IC(50) for FabF(b)[I108] was 50-fold higher (5 microM). These biochemical data explain the absence of an overt growth defect coupled with the cerulenin resistance phenotype of the mutant strain.

Cephalic spreading levels after volumetric caudal epidural injections in chronic low back pain

The volumetric caudal epidural steroid injection has been advocated to facilitate the delivery of medications to the lesion site. This study was aimed to examine the actual spreading patterns of this technique, using epidurogram. A total of 32 patients with chronic low back pain accompanied by radiculopathy of various causes (degenerative spondylosis, herniated nucleus pulposus, spondylolisthesis, and spinal stenosis) were included. The volumetric caudal epidural injection of the 10 mL mixture of contrast medium 5 mL, 0.5% bupivacaine 1 mL, triamcinolone 1.5 mL (60 mg) and normal saline 25 mL was performed. Immediately after the cessation of the first spread, the subsequent solution of another 10 mL of contrast medium 5 mL, 0.5% bupivacaine 1 mL and normal saline 4 mL was injected. This procedure was repeated serially until the total volume to be 50 mL. Continuous fluoroscopic imaging was obtained after each injection. Average time taken to complete the study was 37 sec per every 10 mL. The spreading levels of the mixture were distributed mainly at mid to lower lumbar area in the majority of the patients. During the subsequent injections, the levels were not changed significantly. This was thought to be due to the minimal resistance in cephalad direction, anatomic variations and Starling effect of epidural space.

Long-term outcome of kidney transplantation in adult recipients with focal segmental glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS) is an important cause of nephrotic syndrome and end-stage renal disease. FSGS recurrence after renal transplantation has a potentially detrimental course leading to the loss of renal function. In order to establish FSGS recurrence rates and evaluate the course of the disease on living-related-donor renal transplantation in ethnic Korean adults (> or = 18 years), we reviewed our experiences of 27 kidney transplantations with FSGS over the last 15 years. Of the 27 renal allografts, 13 were found to have recurrent FSGS by graft biopsy. In comparison with background data upon patients with and without recurrence of FSGS, the donor age of patients with recurrent FSGS was significantly higher than that of those without recurrence (median, 39 years vs 26, p < 0.05). In terms of, age at transplantation, length of dialysis period, and mode of dialysis no differences were found between recurrent and nonrecurrent cases. The graft survival rate of recipients from a kidney donor of age less than 40 years was significantly higher than that of recipients from a kidney donor of age more than 40 years, at 5 and 10 years, respectively (87% vs 33%, 41% vs 0%, p < 0.05). The association between clinical variables and recurrence was assessed by multiple logistic regression analysis, and donor age was found to be a risk factor of FSGS recurrence (p<0.05). Variables such as HLA-mismatch numbers and immunosuppression were not found to be associated. In conclusion, the recurrence rate of FSGS in adult recipients with FSGS was 48% and patients that received kidney from an older donor appear to be at higher risk of developing recurrence. The use of a renal graft from a younger donor is considered advisable for adult recipients with FSGS.

An analysis of 4,514 cases of renal biopsy in Korea

To evaluate the distribution and changing patterns of renal diseases in Korea, a total of 4,514 cases of renal biopsy collected over a 23-year period between 1973 and 1995 were reviewed. Of 4,200 cases excluding 314 unsatisfactory biopsies, adult cases comprised 59.5% and pediatric cases, 40.5%. The male to female ratio was 1.5:1 in adults and 2.2:1 in children. Glomerulonephritis (GN) comprised 80.0% of the total. The most common primary GN in adults was minimal change disease (MCD) (26.6%), followed by IgA nephropathy (IgAN) (22.1%), membranous GN (MGN) (11.8%), and membranoproliferative GN (MPGN) (5.9%). In children, the primary GN incidence rates were MCD (24.8%), IgAN (10.3%), poststreptococcal (including postinfectious) GN (PSGN) (8.6%), and focal segmental glomerulosclerosis (FSGS) (4.0%). The most common secondary GN in adults was lupus nephritis and in children Henoch-Schonlein purpura nephritis. The most common cause of nephrotic syndrome was MCD in both adults and children, followed by MGN and FSGS. The elderly, aged sixty years and older, comprised 2.7% of cases and recorded equal numbers of MCD and MGN. The proportion of the biopsies found to be seropositive for HBs antigen was 27.9%, and these showed either MGN or MPGN pattern. Repeat biopsy was performed in 168 patients, due to previous biopsy failure in 15.5%. When the primary GN cases were analyzed at 5-year intervals, the prevalence of PSGN, which was greater than 25% during the 1973-1982 period, decreased abruptly in children thereafter, whereas the prevalence of FSGS increased slowly since the 1988-1992 period in both adults and children. The decrease of PSGN and the increase of FSGS suggest a role for socioeconomic and environmental factors in Korea.

Inhibition of beta-ketoacyl-acyl carrier protein synthases by thiolactomycin and cerulenin. Structure and mechanism

The beta-ketoacyl-acyl carrier protein (ACP) synthases are key regulators of type II fatty acid synthesis and are the targets for two natural products, thiolactomycin (TLM) and cerulenin. The high resolution structures of the FabB-TLM and FabB-cerulenin binary complexes were determined. TLM mimics malonyl-ACP in the FabB active site. It forms strong hydrogen bond interactions with the two catalytic histidines, and the unsaturated alkyl side chain interaction with a small hydrophobic pocket is stabilized by pi stacking interactions. Cerulenin binding mimics the condensation transition state. The subtle differences between the FabB-cerulenin and FabF-cerulenin (Moche, M., Schneider, G., Edwards, P., Dehesh, K., and Lindqvist, Y. (1999) J. Biol. Chem. 244, 6031-6034) structures explain the differences in the sensitivity of the two enzymes to the antibiotic and may reflect the distinct substrate specificities that differentiate the two enzymes. The FabB[H333N] protein was prepared to convert the FabB His-His-Cys active site triad into the FabH His-Asn-Cys configuration to test the importance of the two His residues in TLM and cerulenin binding. FabB[H333N] was significantly more resistant to both antibiotics than FabB and had an affinity for TLM an order of magnitude less than the wild-type enzyme, illustrating that the two-histidine active site architecture is critical to protein-antibiotic interaction. These data provide a structural framework for understanding antibiotic sensitivity within this group of enzymes.

Involvement of caspase-3 in apoptosis induced by Viscum album var. coloratum agglutinin in HL-60 cells

A cytotoxic lectin (Viscum album L. coloratum agglutinin, VCA) from Korean mistletoe was isolated by affinity chromatography on Sepharose 4B immobilized with asialofetuin. In HL-60 cells, addition of VCA resulted in a dose- and time-dependent growth suppression, morphological changes of apoptotic nuclei, and DNA fragmentation characteristics of apoptosis. To investigate how caspase-3 activation during VCA-induced apoptosis induces cleavages of PARP, the expression of PARP and the pattern of caspase-3 activation in HL-60 cells were investigated. The native and processed PARP forms typically seen in apoptotic cells were observed, and a decrease in expression of the 32-kDa form of caspase-3 in a dose-dependent manner was observed. The VCA-induced apoptosis was significantly inhibited by a caspase-3 specific inhibitor, z-DEVD-FMK, and the PARP processing and caspase-3 activation were also inhibited by the inhibitor. A possible involvement of cell cycle arrest in VCA-induced apoptosis was investigated by flow cytometry and the results suggested that the apoptotic effect of VCA is not involved in the induction of cell cycle arrest.

The findings of ruptured hepatocellular carcinoma on helical CT

To evaluate the helical CT findings of ruptured hepatocellular carcinoma (HCC), 12 patients with ruptured HCC were reviewed with regard to the tumour's location, size and contour protrusion, the appearance of the mass, the enhancement pattern, multiplicity and secondary changes. All ruptured tumours were located at the periphery of the liver and had a protruding contour. The maximum diameter of tumours ranged from 2 cm to 16 cm. Discontinuity of the hepatic surface was seen in 11 cases. In eight cases, CT images during the arterial phase showed a non-enhancing low attenuating lesion with focal discontinuity and peripheral rim enhancement. Seven cases showed separation of tumour content from the peripheral enhancing rim and intraperitoneal rupture of tumour content into the perihepatic space. Because of the similar appearance to an enucleated orbital globe with remaining sclera, this was termed the "enucleation sign". As well as ruptured masses, 10 cases with non-ruptured masses also showed a non-enhancing low attenuating pattern. Seven cases showed a haematoma with high attenuation around the ruptured mass. The peripheral location, protruding contour, discontinuity of the hepatic surface and surrounding haematoma are helpful signs in the diagnosis of ruptured HCC. The "enucleation sign" may be a characteristic finding in ruptured HCC.

Live donor renal allograft in end-stage renal failure patients from immunoglobulin A nephropathy

BACKGROUND

The purpose of this study was to attempt to resolve two important issues, i.e. to determine (1) whether the course of recurrent immunoglobulin A nephropathy (IgAN) is benign, and (2) whether it is advisable to use a related donor.

METHODS

We evaluated the long-term outcome, in terms of recurrence and graft survival, after live related or unrelated donor renal transplantation, and assessed the validity of the use of related donors in 90 grafts in 89 IgAN patients.

RESULTS

Ten-year graft survival for IgAN patients was 66%, compared with 84% for 107 reference recipients who had other kinds of glomerulonephritis (GN), and with 69% in 90 other recipients who had non-GN renal failure (P=0.27). In 43 grafts, 54 event graft biopsies were performed, documenting the presence of mesangial IgA deposits in 19 of those grafts. In eight grafts, lesions were accompanied by chronic rejection (CR). Ten-year cumulative recurrence was 44%. Ten grafts were lost: by CR (n=3) or acute rejection (n=1) in 24 recurrence-free recipients, by CR (n=2) or recurrence (n=2) in 19 recurrent patients, and by patient death (n=2) in 46 patients devoid of graft biopsy. We found no difference in 10-year graft survival between the recurrent and recurrence-free patients (63% vs. 74%, P=0.98), or the proportion of related donors (68% vs. 83%, P=0.25). The presence or matching of HLA B12, B35, or DR4 did not affect the recurrence.

CONCLUSIONS

Recurrence increased to 44% with longer follow-up, but this did not limit the graft outcome. Recurrence was not affected by the kind of live donor. We conclude that live related or unrelated kidneys should be offered to IgAN patients.

Intraventricular hemorrhage caused by lateral ventricular meningioma: a case report

Meningiomas causing intracranial hemorrhage are rare, and hemorrhage from a lateral ventricular meningioma seems to be even rarer. We report a case of trigonal meningioma in a 43-year-old woman who presented with intraventricular hemorrhage, and describe the CT, MRI and angiographic findings.