Erratum to: Antimicrobials: a global alliance for optimizing their rational use in intra-abdominal infections (AGORA)

[This corrects the article DOI: 10.1186/s13017-016-0089-y.].

In vivo markers of inflammatory response in recent-onset schizophrenia: a combined study using [(11)C]DPA-713 PET and analysis of CSF and plasma

Several lines of evidence suggest aberrant immune response in schizophrenia, including elevated levels of cytokines. These cytokines are thought to be produced by activated microglia, the innate immune cells of the central nervous system. However, increase in translocator protein 18 kDa (TSPO), a marker of activated glia, has not been found in patients with chronic schizophrenia using second-generation radiotracers and positron emission tomography (PET)-based neuroimaging. In this study we focused on patients with recent onset of schizophrenia (within 5 years of diagnosis). Quantified levels of TSPO in the cortical and subcortical brain regions using the PET-based radiotracer [(11)C]DPA-713 were compared between the patients and healthy controls. Markers of inflammation, including interleukin 6 (IL-6), were assessed in the plasma and cerebrospinal fluid (CSF) in these participants. We observed no significant change in the binding of [(11)C]DPA-713 to TSPO in 12 patients with recent onset of schizophrenia compared with 14 controls. Nevertheless, the patients with recent onset of schizophrenia showed a significant increase in IL-6 in both plasma (P<0.001) and CSF (P=0.02). The CSF levels of IL-6 were significantly correlated with the levels of IL-6 in plasma within the total study population (P<0.001) and in patients with recent onset of schizophrenia alone (P=0.03). Our results suggest that increased levels of IL-6 may occur in the absence of changed TSPO PET signal in the brains of medicated patients with recent onset of schizophrenia. Future development of PET-based radiotracers targeting alternative markers of glial activation and immune response may be needed to capture the inflammatory signature present in the brains of patients with early-stage disease.

Decoupling of N-acetyl-aspartate and glutamate within the dorsolateral prefrontal cortex in schizophrenia

Aberrant function of glutamatergic pathways is likely to underlie the pathology of schizophrenia. Evidence of oxidative stress in the disease pathology has also been reported. N-Acetylaspartate (NAA) is metabolically linked to both cascades and may be a key marker in exploring the interconnection of glutamatergic pathways and oxidative stress. Several studies have reported positive correlation between the levels of NAA and Glx (the sum of glutamate and glutamine) in several brain regions in healthy subjects, by using proton magnetic resonance spectroscopy ([(1)H]MRS). Interestingly, one research group recently reported decoupling of the relationship between NAA and Glx in the hippocampus of patients with schizophrenia. Here we report levels of NAA and Glx measured using [(1)H]MRS, relative to the level of creatine (Cr) as an internal control. The dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC) in 25 patients with schizophrenia and 17 matched healthy controls were studied. In DLPFC, NAA/Cr and Glx/Cr were significantly positively correlated in healthy controls after correction for the effect of age and smoking status and after correction for multiple comparisons (r= 0.627, P= 0.017). However, in patients with schizophrenia, the positive correlation between NAA/Cr and Glx/Cr was not observed even after correcting for these two variables (r= -0.330, P= 0.124). Positive correlation between NAA/Cr and Glx/Cr was not observed in the ACC in both groups. Decoupling of NAA and Glx in the DLPFC may reflect the interconnection of glutamatergic pathways and oxidative stress in the pathology of schizophrenia, and may possibly be a biomarker of the disease.

Multiple pathways for protein transport to peroxisomes

Peroxisomes are unique among the organelles of the endomembrane system. Unlike other organelles that derive most if not all of their proteins from the ER (endoplasmic reticulum), peroxisomes contain dedicated machineries for import of matrix proteins and insertion of membrane proteins. However, peroxisomes are also able to import a subset of their membrane proteins from the ER. One aspect of peroxisome biology that has remained ill defined is the role the various import pathways play in peroxisome maintenance. In this review, we discuss the available data on matrix and membrane protein import into peroxisomes.

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Peroxisomal membrane and matrix proteins require distinct factors for their transport.

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Matrix proteins fold in the cytosol prior to their import.

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Loaded targeting receptors form part of the matrix protein translocation pore.

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Many membrane proteins are directly inserted into the peroxisomal membrane.

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Some peroxisomal membrane proteins are transported via the ER to peroxisomes.

A multicentre, multinational, randomized, placebo-controlled, double-blind, phase 3 trial to evaluate the efficacy and safety of gemigliptin (LC15-0444) in patients with type 2 diabetes

AIM

This study was designed to assess the efficacy and safety of the dipeptidyl peptidase IV inhibitor gemigliptin (LC15-0444) 50 mg versus placebo in patients with type 2 diabetes.

METHODS

We conducted a 24-week, randomized, double-blind, placebo-controlled phase III trial in 182 patients (74 from Korea and 108 from India) with type 2 diabetes. After an initial 2 weeks of a diet and exercise programme followed by 2 weeks of a single-blind placebo run-in period, eligible patients were randomized to gemigliptin 50 mg or placebo, receiving the assigned treatment for 24 weeks. HbA1c and fasting plasma glucose (FPG) were measured periodically, and oral glucose tolerance test was performed at baseline and weeks 12 and 24.

RESULTS

At week 24, gemigliptin treatment led to significant reductions in HbA1c measurements compared to placebo (adjust mean after subtracting the placebo effect size: -0.71%, 95% confidence interval: -1.04 to -0.37%). A significantly greater proportion of patients achieved an HbA1c <7% with gemigliptin than with placebo. The placebo-subtracted FPG change from baseline at week 24 was -19.80 mg/dl. The overall incidence rates for adverse events were similar in the gemigliptin and placebo groups.

CONCLUSIONS

This study showed the efficacy and safety of gemigliptin 50 mg administered once daily as a monotherapy for type 2 diabetes patients.

Vena cava filters: a synopsis of complications and related topics

Deep venous thrombosis and pulmonary embolism constitute common preventable causes of morbidity and mortality. The incidence of venous thromboembolism (VTE) continues to increase. Standard anticoagulation therapy may reduce the risk of fatal PE by 75% and that of recurrent VTE by over 90%. For patients who are not candidates for anticoagulation, a vena cava filter (VCF) may be beneficial. Despite a good overall safety record, significant complications related to VCF are occasionally seen. This review discusses both procedural and non-procedural complications associated with VCF placement and use. We will also discuss VCF use in the settings of pregnancy, malignancy, and the clinical need for more than one filter.

Nitric oxide suppresses the expression of Bcl-2 binding protein BNIP3 in hepatocytes

Nitric oxide (NO) is not only an important signaling molecule, but it also regulates the expression of a number of genes in the liver. We have previously shown that apoptosis in hepatocytes exposed to tumor necrosis factor-alpha and actinomycin D is prevented by NO derived from the inducible nitric-oxide synthase (iNOS), by mechanisms that are both dependent on and independent of modulation of cyclic guanosine monophosphate (cGMP) subsequent to activation of soluble guanylyl cyclase (sGC). We hypothesize that one mechanism by which NO exerts these effects is by regulating the expression of genes involved in apoptosis. We used differential display-polymerase chain reaction to isolate NO-regulated genes in hepatocytes from iNOS knockout mice (to eliminate endogenous inducible NO production). Using this analysis, we identified a NO-suppressed gene fragment homologous with the pro-apoptotic Bcl-2 binding protein BNIP3. Northern analysis confirmed the NO-dependent suppression of BNIP3 in cultured cells. Similarly, the NO donor S-nitroso-N-acetyl-dl-penicillamine (1-1000 microm) down-regulated the expression of BNIP3 in both iNOS knockout and wild-type hepatocytes. This effect of NO was reversed by the sGC inhibitor 1H-(1,2,4)-oxadiazole[4,3-a]quinoxalon-1-one (ODQ),suggesting the involvement of the sGC/cGMP pathway in the modulation of BNIP3 by NO. We propose that suppression of BNIP3 expression is one sGC/cGMP-dependent mechanism by which NO might affect the process of hepatocyte apoptosis.

The role of caspase-8 in resistance to cancer chemotherapy

Toxicity of chemotherapeutic agents against cancer cells is mediated through the initiation of programmed cell death. Apoptosis is an evolutionarily conserved cascade of intracellular proteolytic events propagated by a family of cysteine proteases called caspases. Many receptor- and non-receptor-mediated death signals induce apoptosis via activation of caspase-8 (FLICE/MACH). Mechanisms of tumor resistance to cytotoxic drugs through decreased apoptosis may occur by altered expression of caspase-8, upregulation of caspase-8 inhibitors like FLIP (FLICE-like Inhibitory Protein), or sequestration of caspase-8 by Bcl-2. Modulation of caspase-8 and apoptosis may be a therapeutic strategy for sensitization of drug-resistant malignancies to radiation or combination chemotherapy.

The regulatory role of nitric oxide in apoptosis

Nitric oxide (NO) is a multi-faceted molecule with dichotomous regulatory roles in many areas of biology. The complexity of its biological effects is a consequence of its numerous potential interactions with other molecules such as reactive oxygen species (ROS), metal ions, and proteins. The effects of NO are modulated by both direct and indirect interactions that can be dose-dependent and cell-type specific. For example, in some cell types NO can promote apoptosis, whereas in other cells NO inhibits apoptosis. In hepatocytes, NO can inhibit the main mediators of cell death-caspase proteases. Moreover, low physiological concentrations of NO can inhibit apoptosis, but higher concentrations of NO may be toxic. High NO concentrations lead to the formation of toxic reaction products like dinitrogen trioxide or peroxynitrite that induce cell death, if not by apoptosis, then by necrosis. Long-term exposure to nitric oxide in certain conditions like chronic inflammatory states may predispose cells to tumorigenesis through DNA damage, inhibition of DNA repair, alteration in programmed cell death, or activation of proliferative signaling pathways. Understanding the regulatory mechanisms of NO in apoptosis and carcinogenesis will provide important clues to the diagnosis and treatment of tissue damage and cancer. In this article we have reviewed recent discoveries in the regulatory role of NO in specific cell types, mechanisms of pro-apoptotic and anti-apoptotic induction by NO, and insights into the effects of NO on tumor biology.

Compensatory hepatic regeneration after mild, but not fulminant, intraperitoneal sepsis in rats

Sepsis is the leading cause of death in surgical intensive care units. Although both mild sepsis secondary to cecal ligation and single puncture (CLP) and fulminant, double puncture CLP (2CLP) may provoke hepatocyte death, we hypothesize that regeneration compensates for cell death after CLP but not 2CLP. In male Sprague-Dawley rats, hepatic necrosis, as determined by serum alpha-glutathione S-transferase (alpha-GST) levels, was significantly but equally elevated over time after both CLP and 2CLP. Apoptosis, evaluated using both terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling and morphological examination, was minimal after both CLP and 2CLP. Regeneration, assayed by staining tissue for incorporation of exogenously administered bromodeoxyuridine, was present after CLP but not after 2CLP. To further substantiate impaired regeneration, steady-state levels of mRNAs encoding JunB, LRF-1, and cyclin D1 were determined. After 2CLP, the absence of JunB, LRF-1, and cyclin D1 mRNAs confirmed failed activation of the mitogen-activated protein kinase-linked proliferative pathway and progression through the cell cycle. Therefore, failed hepatocyte regeneration may be a manifestation of hepatic dysfunction in fulminant sepsis.

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.

Glomerular growth under cyclosporine treatment in childhood nephrotic syndrome

BACKGROUND

Glomerular hypertrophy is important in children with idiopathic nephrotic syndrome in regard to diagnosis and pathogenesis. Moreover, glomerular growth may be altered by cyclosporine (CsA) treatment in these patients.

METHODS

Bowman's area (BA) and the glomerular tuft area (GA) of pre- and post-treatment biopsies was measured by morphometry in 47 children with idiopathic nephrotic syndrome (39 MCD and 8 FSGS) treated with CsA and low-dose prednisolone for up to 2 years.

RESULTS

BA and GA increased with age. The mean BA and GA were 1.2 times larger in FSGS than in MCD and the proportional increase was similar in both diseases after treatment. BA and GA decreased in 48.9% and 40.4% of cases after treatment, respectively, whereas tubulointerstitial lesion (TIL) developed in 27.7%. BA and GA decreased to 10.4% and 8.3%, respectively in children who developed TIL after treatment and the values were largely unchanged in those treated for more than 16 months.

CONCLUSIONS

Glomerular growth is hampered by CsA nephrotoxicity, which is a more common complication than TIL. The impairment of glomerular growth is related to the duration of treatment and the development of TIL, but not to age or diagnosis.

Intraabdominal sepsis down-regulates transcription of sodium taurocholate cotransporter and multidrug resistance-associated protein in rats

Hepatic dysfunction in sepsis is characterized by hyperbilirubinemia and intrahepatic cholestasis. We hypothesize that sepsis causes decreased hepatic transcription of the bile acid transporter sodium taurocholate cotransporter (Ntcp) and the organic anion transporter multidrug resistance-associated protein (Mrp2) and that interleukin (IL)-6 is important in the down-regulation of Ntcp and Mrp2 expression. Male Sprague-Dawley rats underwent induction of mild, nonlethal sepsis by cecal ligation and single puncture (CLP) or fulminant sepsis by cecal ligation and double puncture (2CLP). Hepatic transcription of Ntcp and Mrp2 rapidly decreased after CLP or 2CLP. Seventy-two hours later, transcription was 60% of baseline in CLP and 14% of baseline in 2CLP. Serum bilirubin was elevated from 24 h onward and cholestasis was observed on fixed liver specimens at 24, 48, and 72 h after 2CLP but not after CLP. Steady-state Ntcp and Mrp2 mRNA was decreased in IL-6-treated cultured hepatocytes and in normal rats given 1 mg/kg intravenous IL-6. We conclude that 1) Ntcp and Mrp2 transcription is down-regulated transiently after CLP and persistently after 2CLP; 2) 2CLP results in hyperbilirubinemia and cholestasis, in part due to persistently decreased transcription of Ntcp and Mrp2; and 3) altered Ntcp and Mrp2 transcription is mediated in part by IL-6.

Inflammatory responses and mediators

The host response to injury is usually appropriate in degree and is self-limited. In more severe injury, the host response may persist inappropriately, leading to SIRS and MODS and possibly multiple organ failure. The initial response to injury is mediated primarily by norepinephrine, and is directed toward preservation of circulation to the heart and brain at the expense of other vascular beds. If fluid resuscitation is adequate and necrotic tissue is débrided, a hypermetabolic state ensues, mediated by epinephrine and directed toward supporting repair of injured tissue by leukocytes. Inflammatory cells are recruited to the site of injury and elaborate cytokines, which promote repair locally, but in severe injury may be systemically released and trigger remote inflammation. Cytokine biology presently is poorly understood, and simple anticytokine strategies have failed to improve survival of critically ill patients. Current therapy of SIRS and MODS is directed toward symptoms. Presently, it is unclear how an abnormal stress response arises. Cytokine spillover into the systemic circulation may occur. Selective transcriptional failure may be the cellular basis of organ dysfunction. Inappropriate production of peroxynitrite or its precursor, NO, is implicated in mediating cellular injury in SIRS and MODS.

Paclitaxel-induced apoptosis in non-small cell lung cancer cell lines is associated with increased caspase-3 activity

OBJECTIVE

Our objective was to determine whether paclitaxel-induced apoptosis in human lung cancer cells is Fas dependent.

METHODS

Human lung cancer cell lines were evaluated for morphologic evidence of apoptosis, DNA fragmentation (TUNEL positivity), and caspase-3 activation after paclitaxel treatment. Human lung adenocarcinoma, squamous cell carcinoma, undifferentiated lung carcinoma, and bronchoalveolar carcinoma cell lines were each cultured in 10 micromol/L paclitaxel.

RESULTS

After 24 hours of culture in paclitaxel, a 22% to 69% increase in the number of apoptotic cells was evident by means of methylene blue-azure A-eosin staining with characteristic blebbing and nuclear condensation. TUNEL assay also confirmed an increase of 19.9% to 73.0% of cells with nuclear fragmentation. Caspase-3 activity, assayed by Z-DEVD cleavage, increased from 20% to 215% (P <.05). ZB4, an antagonistic anti-Fas antibody, did not block paclitaxel induction of caspase-3 activity (155.8 vs 165.8 U, not significant). Apoptotic morphologic changes were inhibited in cells cultured in the presence of paclitaxel and Ac-DEVD-CHO, a caspase-3 inhibitor.

CONCLUSIONS

Paclitaxel induces apoptosis in lung cancer cell lines, as assessed by a consistent increase in caspase-3 activity, DNA laddering, and characteristic morphologic changes. Paclitaxel-induced apoptosis in human lung cancer cells is associated with caspase-3 activation but is not Fas dependent.

Identification of the endoplasmic reticulum targeting signal in vesicle-associated membrane proteins

The vesicle-associated membrane proteins (Vamp(s)) function as soluble N-ethylmaleimide-sensitive factor attachment receptor proteins in the intracellular trafficking of vesicles. The membrane attachment of Vamps requires a carboxyl-terminal hydrophobic sequence termed an insertion sequence. Unlike other insertion sequence-containing proteins, targeting of the highly homologous Vamp1 and Vamp2 to the endoplasmic reticulum requires ATP and a membrane-bound receptor. To determine if this mechanism of targeting to the endoplasmic reticulum extends to other Vamps, we compared the membrane binding of Vamp1 and Vamp2 with the distantly related Vamp8. Similar to the other Vamps, Vamp8 requires both ATP and a membrane component to target to the endoplasmic reticulum. Furthermore, binding curves for the three Vamps overlap, suggesting a common receptor-mediated process. We identified a minimal endoplasmic reticulum targeting domain that is both necessary and sufficient to confer receptor-mediated, ATP-dependent, binding of a heterologous protein to microsomes. Surprisingly, this conserved sequence includes four positively charged amino acids spaced along an amphipathic sequence, which unlike the carboxyl-terminal targeting sequence in mitochondrial Vamp isoforms, is amino-terminal to the insertion sequence. Because Vamps do not bind to phospholipid vesicles, it is likely that these residues mediate an interaction with a protein, rather than bind to acidic phospholipids. Therefore, we suggest that a bipartite motif is required for the specific targeting and integration of Vamps into the endoplasmic reticulum with receptor-mediated recognition of specifically configured positive residues leading to the insertion of the hydrophobic tail into the membrane.

Pediatric peritoneal dialysis in Korea: practical solutions to the problems of peritoneal dialysis for children

PURPOSE

To find and solve the common problems of peritoneal dialysis (PD) by analyzing the clinical data of pediatric PD performed in Korea.

METHODS

We looked at 264 cases of continuous ambulatory peritoneal dialysis (CAPD) and acute PD that were performed in 18 institutions of pediatric nephrology in Korea from November 1987 to October 1997.

RESULTS

CAPD was performed in 114 cases. The mean age of the patients was 10.5+/-6.6 years, and the male-to-female ratio was 1.4:1. The original causes of end-stage renal disease (ESRD) were proven in 92 cases (81%). The most common renal diseases were focal segmental glomerulosclerosis (17%), reflux nephropathy (11%), and chronic glomerulonephritis (11%). Mean duration of CAPD was 20 months+/-16.9 months. Peritonitis was the most common complication, and the peritonitis incidence was 0.96 episode per patient-year. Other complications were exit-site infection in 10 cases, obstruction in 7 cases, and leakage of dialysate in 6 cases. The most common etiologic organism of peritonitis was Staphylococcus aureus and the next most common was coagulase-negative staphylococcus. Acute PD was performed in 150 cases. The most common underlying causes were congenital heart disease, hemolytic uremic syndrome, sepsis, and dehydration. The mean duration was 10.3+/-11.3 days. The most common complication was peritonitis (78.3%). The most common etiologic organisms of peritonitis were Staphylococcus aureus, coag-neg staphylococcus, Acinetobacter, and Pseudomonas.

CONCLUSION

Reflux nephropathy should be emphasized in early diagnosis and treatment to prevent ESRD. Incidence of congenital anomaly (7%) as a original cause of ESRD was relatively low in Korea. Growth status was not significantly improved after CAPD. In acute PD, the incidence of peritonitis rapidly increased at 2 weeks after the start of dialysis.

Results of kidney transplantation from 1979 to 1997 at Yonsei University

1. Long-term graft survival markedly improved after the introduction of CsA as the main immunosuppressant in living-donor kidney transplantation at our institution. 2. HLA-identical LRD kidney transplantation provided the best long-term graft survival rate, probably due to a decreased incidence of graft loss from rejection. 3. We could achieve good long-term graft survival in LURD kidney transplantation compared with that of HLA-haploidentical LRD kidney transplantation. 4. Because of the striking discrepancy between organ donation and the increasing demand for transplantation, distant relative donors and LURDs, including swap donors, should be considered as an alternative way to increase the number of available donors when accompanied by a careful evaluation process.

Analysis of the envelope region of hepatitis G virus isolated from Korean patients

The genetic diversity of hepatitis G virus (HGV) was investigated. By using a RT-PCR procedure, 14% of either HBV (hepatitis B virus)- or HCV (hepatitis C virus)-positive Korean hepatitis patients were proved to be HGV positives. Nucleotide sequences in the E1 region of the eight isolates from Korean patients and the six previously reported isolates were compared. Nucleotide substitutions spread uniformly throughout the E1 region. Sequence homology among the Korean isolates was 84-99% and 88-99% at the nucleotide and amino acid sequences, respectively, whereas those from different geographic areas was slightly lower at both levels. At least two genotypes might exist among the Korean HGV isolates. Compared to the corresponding region of HCV, the E1 sequence from HGV is moderately conserved. In addition, as frameshift mutations were observed in most of the Korean isolates compared to the prototype HGV sequence, the Korean isolates might not use the translational initiation site of the prototype HGV for polyprotein translation. Because a putative signal sequence of E1 for entry into endoplasmic reticulum starts from the N-terminus of the polyprotein, and capsid-like peptides composed of basic amino acids could not be detected from the upstream region of E1, the core protein of HGV is absent, or at least not present, at the region next to 5'-UTR. Therefore, HGV could be clearly distinguished from other genera of Flaviviridae.

Long-term results of cyclosporine-induced remission of relapsing nephrotic syndrome in children

Twenty-nine children with nephrotic syndrome were treated with cyclosporine (CsA), 100 mg/m2/day for 6 months and prednisone, 2 mg/kg every other day for 1 month and then subsequently 1 mg/kg every other day for 5 months. A renal biopsy had shown minimal change disease (MCD) in 18 children, focal segmental glomerulosclerosis (FSGS) in 3 children, membranous glomerulonephritis (MGN) in 4 children, membranoproliferative glomerulonephritis (MPGN) in 2 children, and IgA nephropathy in 2 children. All MCD patients went into complete remission during therapy. Five out of 11 steroid-sensitive patients (45.5%) remained in complete remission, while the remaining 6 (54.5%) had 2 to 3 relapses, 19 to 47 months after CsA discontinuation. Two out of 7 steroid-resistant patients (28.6%) were still in complete remission and 5 (71.4%) had 1 to 6 relapses 25 to 49 months after CsA withdrawal. The mean number of relapses in the steroid-sensitive group before and after CsA treatment decreased more (8.5 vs 1.4) than in the steroid-resistant group (8.1 vs 2.4) (p < 0.05). At the most recent examination, 1 of 3 FSGS patients achieved complete remission and 2 had a partial response. Three of 4 MGN patients were in complete remission and 1 was in partial remission. One of 2 MPGN patients achieved complete remission and 1 showed partial remission. Two patients with IgA nephropathy were in partial remission. We compared MCD patients in sustained remission and relapse; the mean CD4/CD8 ratio decreased from 1.5 to 0.9 in the remission group, in comparison with no change in the relapsed group (p < 0.05). The posttreatment renal biopsy showed lesions of nephrotoxicity in 3 of 18 children with MCD whose renal function did not alter after CsA treatment. We concluded: 1) A 6-month treatment of CsA, in combination with a low-dose alternate-day steroid, proved to be effective in maintaining the remission of steroid-sensitive and steroid-resistant MCD patients. 2) The CD4/CD8 ratio can be used as a index to predict remission or relapse after CsA therapy.

Evidence for multiple mechanisms for membrane binding and integration via carboxyl-terminal insertion sequences

Subcellular localization of proteins with carboxyl-terminal insertion sequences requires the molecule be both targeted to and integrated into the correct membrane. The mechanism of membrane integration of cytochrome b5 has been shown to be promiscuous, spontaneous, nonsaturable, and independent of membrane proteins. Thus endoplasmic reticulum localization for cytochrome b5 depends primarily on accurate targeting to the appropriate membrane. Here direct comparison of this mechanism with that of three other proteins integrated into membranes via carboxyl-terminal insertion sequences [vesicle-associated membrane protein 1(Vamp1), polyomavirus middle-T antigen, and Bcl-2] revealed that, unlike cytochrome b5, membrane selectivity for these molecules is conferred at least in part by the mechanisms of membrane integration. Bcl-2 membrane integration was similar to that of cytochrome b5 except that insertion into lipid vesicles was inefficient. Unlike cytochrome b5 and Bcl-2, Vamp1 binding to canine pancreatic microsomes was saturable, ATP-dependent, and abolished by mild trypsin treatment of microsomes. Surprisingly, although the insertion sequence of polyomavirus middle-T antigen was sufficient to mediate electrostatic binding to membranes, binding did not lead to integration into the bilayer. Together these results demonstrate that there are at least two different mechanisms for correct membrane integration of proteins with insertion sequences, one mediated primarily by targeting and one relying on factors in the target membrane to mediate selective integration. Our results also demonstrate that, contrary to expectation, hydrophobicity is not sufficient for insertion sequence-mediated membrane integration. We suggest that the structure of the insertion sequence determines whether or not specific membrane-bound receptor proteins are required for membrane integration.

Genomic structure and mapping of human FADD, an intracellular mediator of lymphocyte apoptosis

Fas-associated death domain protein (FADD)/MORT1 is a 23-kDa cytoplasmic protein containing a C-terminal death domain that interacts with the intracellular death domain of the Fas transmembrane receptor. Cross-linking of Fas mediates apoptosis in a variety of cells, primarily peripheral T lymphocytes, for which this pathway plays a major role in mature lymphocyte homeostasis. We report the characterization of the human FADD gene, which spans approximately 3.6 kb and contains two exons (286 and 341 bp) separated by a 2.0-kb intron. FADD was mapped to chromosome 11q13.3 by the independent techniques of PCR screening of somatic cell hybrid mapping panels and fluorescence in situ hybridization. In addition FADD was shown by fluorescence in situ hybridization to be amplified along with other 11q13.3 genes previously studied in the breast cancer cell line MDA-MB-134-VI, raising the possibility that overexpression of mutant FADD could contribute to poor prognosis and increased invasiveness of tumors. Its known role in apoptosis has made FADD a candidate susceptibility gene for autoimmune lymphoproliferative syndrome. Now that it has been colocalized in 11q13.3 with IDDM4, a diabetes susceptibility locus, alterations in FADD should also be considered as potential contributors to insulin-dependent familial diabetes. Elucidation of the map position and gene structure of FADD will make possible linkage and mutation analysis to study the role of this gene in human diseases.

Genomic structure and mapping of human FADD, an intracellular mediator of lymphocyte apoptosis

Fas-associated death domain protein (FADD)/MORT1 is a 23-kDa cytoplasmic protein containing a C-terminal death domain that interacts with the intracellular death domain of the Fas transmembrane receptor. Cross-linking of Fas mediates apoptosis in a variety of cells, primarily peripheral T lymphocytes, for which this pathway plays a major role in mature lymphocyte homeostasis. We report the characterization of the human FADD gene, which spans approximately 3.6 kb and contains two exons (286 and 341 bp) separated by a 2.0-kb intron. FADD was mapped to chromosome 11q13.3 by the independent techniques of PCR screening of somatic cell hybrid mapping panels and fluorescence in situ hybridization. In addition FADD was shown by fluorescence in situ hybridization to be amplified along with other 11q13.3 genes previously studied in the breast cancer cell line MDA-MB-134-VI, raising the possibility that overexpression of mutant FADD could contribute to poor prognosis and increased invasiveness of tumors. Its known role in apoptosis has made FADD a candidate susceptibility gene for autoimmune lymphoproliferative syndrome. Now that it has been colocalized in 11q13.3 with IDDM4, a diabetes susceptibility locus, alterations in FADD should also be considered as potential contributors to insulin-dependent familial diabetes. Elucidation of the map position and gene structure of FADD will make possible linkage and mutation analysis to study the role of this gene in human diseases.

Manipulation of peptide conformations by fine-tuning of the environment and/or the primary sequence

The widely observed phenomenon that peptides are capable of adopting multiple conformations in different environments suggests that secondary structure formation in a peptide segment is a process involving not only the peptide itself but also the surrounding solvent media. The influence of the primary sequence and the molecular environment on peptide conformations are now investigated using synthetic peptides of amino acid sequence H2N-(Ser-Lys)2-Ala-X-Gly-Ala-X-Gly-Trp-Ala-X-Gly-(Lys-Ser)3-OH, where X = Ile or Val. These two peptides, namely 3I (X = Ile) and 3V (X = Val), are found to lack defined secondary structure in aqueous buffer. However, discrete conformational states, e.g., alpha-helices and beta-sheets, are readily generated and interconverted for both peptides when the buffer is modulated with the addition of methanol, sodium dodecyl sulfate (SDS) micelles, or phospholipid vesicles. The role of the primary sequence in affecting peptide conformations is manifested in that peptides 3I and 3V, which differ respectively in their content of beta-branched Ile or Val residues, differ in their secondary structures at monomeric concentrations in 2 mM SDS and in mixed lipid vesicles of phosphatidic acid and phosphatidylcholine. The overall results suggest that peptide segments can be conformationally flexible entities poised to react to minor modulation in either the molecular environment or the primary sequence, a circumstance that may be relevant to protein functioning and folding.

Rapid culture and quantitation of human immunodeficiency virus type 1 from patient cells without the use of mitogen-stimulated donor cells

We report the development of a rapid, sensitive virus culture method for direct quantitation of human immunodeficiency virus (HIV) in peripheral blood mononuclear cells (PBMCs). This new method involves culturing 10(7) PBMCs from HIV-seropositive persons in 10 ml of medium containing phorbol 12-myristate 13-acetate and interleukin-2. Both agents stimulate cell activation and hence viral replication. Cell-associated virus and free virus are quantitated by a commercially available HIV p24 antigen capture enzyme immunoassay. Detection of cell-associated p24 antigen by flow cytometry was less sensitive than by the enzyme immunoassay. In this preliminary study, HIV was detected in 20 of 23 HIV-seropositive patients and in none of the 11 HIV seronegative low-risk individuals. One HIV-seronegative person with Guillain-Barré syndrome following high-risk activity was found to be rapid-HIV-culture positive. The overall sensitivity and specificity were 87 and 100%, respectively. By comparing the quantity of virus produced in infected cells with the amount of virus produced in chronically infected U1 monocytes and ACH-2 lymphocytes stimulated with phorbol 12-myristate 13-acetate and interleukin-2, the approximate number of infected cells per sample is calculated. In the same patient specimens, quantitation of the number of HIV infected cells by the HIV rapid-culture method correlated with the results of the 21-day cell dilution coculture assay (correlation coefficient r = 0.5; 95% confidence interval, 0.07 to 0.77). Advantages of the rapid HIV culture include no requirement for donor PBMCs or change of media, shortened culture time, and the ability to detect p24 viral antigen from cell-associated virus for quantitation of viral load.

Cyclosporin A sensitivity of the NF-kappa B site of the IL2R alpha promoter in untransformed murine T cells

We have investigated the characteristics of IL2R alpha gene induction in untransformed murine T cells. Induction of IL2R alpha mRNA by TCR/CD3 ligands in a murine T cell clone and in short-term splenic T cell cultures was inhibited by protein synthesis inhibitors and by CsA. This result was contrary to previous observations in JURKAT T leukemia cells and human peripheral blood T cells, suggesting a difference in the mechanisms of IL2R alpha gene induction in these different cell types. The CsA sensitivity of IL2R alpha mRNA induction represented a direct effect on the TCR/CD3 response, and was not due to CsA-sensitive release of the lymphokines IL2 or tumour necrosis factor alpha (TNF alpha) and consequent lymphokine-mediated induction of IL2R alpha mRNA. The NF-kappa B site of the IL2R alpha promoter was essential for gene induction through the TCR/CD3 complex, and the induction of reporter plasmids containing multimers of this site was significantly inhibited by CsA. Northern blotting analysis indicated that while the p65 subunit of NF-kappa B was constitutively expressed and not appreciably induced upon T cell activation, mRNA for the p105 precursor of p50 NF-kappa B was induced in response to TCR/CD3 stimulation and this induction was sensitive to CsA. Electrophoretic mobility shift assays and antiserum against the p50 subunit of NF-kappa B indicated that p50 was a component of the inducible nuclear complex that bound to the IL2R alpha kappa B site. Appearance of the kB-binding proteins was insensitive to CsA at early times after activation (approximately 15 min), but was partially sensitive to CsA at later times. Based on these results, we propose that the NF-kappa B site of the IL2R alpha promoter mediates at least part of the CsA sensitivity of IL2R alpha gene induction in untransformed T cells, possibly because de novo synthesis of p105 NF-kappa B is required for sustained IL2R alpha expression.

An analysis of 2361 cases of renal biopsy in Korea

To evaluate the distribution pattern of renal diseases based on needle biopsy, we analyzed 2361 cases of renal biopsy and necropsy material examined at the Department of Pathology from 1973 to 1988. The average age was 21.1 years for males and 23.7 years for females. The adult cases comprised 60.2% and the child cases 39.8%. The male to female ratio was 1.6: 1 in adults and 2.3:1 in children. Glomerular diseases were 97.8% of the total; primary glomerulonephritis (GN) 59.8% and secondary GN 27.6% The major glomerular diseases, in descending order of frequency, were; minimal change nephrotic syndrome (MCNS; 24.2%), IgA nephropathy (IgAN; 17.8%), benign recurrent hematuria (BRH; 8.8%), membranous GN (MGN; 7.9%), acute poststreptococcal GN (APSGN; 7.3%), mesangioproliferative GN (MspGN; 5.5%), minimal mesangiopathy (5.5%), membranoproliferative GN(4.1%), and focal segmental glomerulosclerosis (FSGS; 2.7%). GN of systemic disease included 77 cases of lupus nephritis, 157 cases of Henoch-Schönlein purpura nephritis (HSPN) and 7 cases of systemic infection excluding Hepatitis B viral hepatitis. The most common glomerular diseases were MCNS, IgAN, MGN and MspGN in adults, and MCNS, BRH, HSP-N and APSGN in children. HBs antigenemia was found in 71 cases, of which MGN and IgAN were the most frequent. HBs antigenemia-associated MGN was prevalent in male children, whereas IgAN was prevalent in adults.(ABSTRACT TRUNCATED AT 250 WORDS)

Significance of mesangial IgA deposition in minimal change nephrotic syndrome: a study of 60 cases

We studied 60 cases of minimal change nephrotic syndrome (MCNS) with mesangial IgA deposits occurring over a 6 year period. There were 43 adults and 17 children. Hematuria occurred in 69.0% of the adults and 88.2% of the children. Two adults and six children had gross hematuria during the course of the disease. Mesangial IgA deposits were noted in 100% of the cases, and concomitant IgG or IgM deposits were found in 78.6% of adults and 73.7% of children. The fluorescent intensity of mesangial IgA deposits was trace (+/-) to 1+ in 86.1% and 70.6% of the adults and children respectively. Most of the patients showed electron microscopic findings consistent with minimal change nephrotic syndrome. We speculate that most of our cases are variants of minimal change nephrotic syndrome but are neither IgA nephropathy nor an overlapping syndrome, and that environmental or genetic factors may be related to the deposition of IgA in these MCNS patients.

[The prevalence of head louse infestation among urban and rural children in Korea]

The prevalence of head louse (Pediculus hamanus var. capitis) infestation in preschool and school children in 9 urban and 8 rural areas of Korea, was investigated. Of 11,865 children who were examined for head lice and nits, 2,900(24.4%) were found infested. The over-all infestation rate of rural children, 58.9%, was higher than that of urban children, 14.4%. There also existed significant differences in the infestation rate among various regions of urban as well as rural areas. Females were more infested than males. But there was no differences in infestation rate in either sex of preschool age. The infestation rate increased gradually from the age of 6, reached a plateau between 9-12 years of age and thereafter slowly decreased. The infestation rate of an orphanage children was higher than that of general childhood population. Health education and mass-delousing attempt are urgently required to lower such a high prevalence of head louse infestation in Korea.

Transluminal angioplasty in patients with bilateral renal artery stenosis or renal artery stenosis in a solitary functioning kidney

Renal angioplasty in patients with bilateral renal artery stenosis or with renal artery stenosis in a solitary functioning kidney has been thought to be relatively contraindicated. We report the results of renal artery angioplasty in 18 patients, 10 with severe bilateral renal artery stenosis and eight with severe renal artery stenosis in a solitary kidney. Twenty-five (89%) of 28 angioplasties were successful, with a mean improvement of the degree of stenosis from 85% to 18% after angioplasty and a restoration of renal blood flow. A significant drop in mean blood pressure at admission of 187/101 mm Hg to 154/87 mm Hg at discharge, 152/86 mm Hg at 3-month, and 146/82 mm Hg at 1-year follow-up was seen. Because of the decrease in blood pressure, 11 of the patients decreased or stopped taking diuretics and 15 decreased or stopped taking antihypertensive medications. Although no significant change in renal function was found by measuring mean serum creatinine levels over time, no patient had an elevated serum creatinine level at follow-up, indicating preservation of renal function. One major complication, cholesterol embolization to the bowel, was seen. Our results suggest that angioplasty is an acceptable treatment of hypertension in patients with bilateral renal artery stenosis or renal artery stenosis in a single kidney.

Steroid effects on minimal lesion nephrotic syndrome with and without immune deposits

A comparison was done between the two groups of MLNS (minimal lesion nephrotic syndrome) with and without mesangial deposits of immunoglobulin and complement. The subjects were 40 patients with MLNS whose kidney could be obtained by biopsy. No significant differences were found between the two groups in selective protein index, serum cholesterol level, serum albumin level, amount of 24 hour urine protein, hematuria, serum immunoglobulin level and response to steroid therapy. Ig M was deposited in eleven of fourteen patients with MLNS, Ig G three of fourteen, C3 thirteen of fourteen. There was no relationship between serum level and glomerular deposition of immunoglobulin and complement.

Cell-mediated immunity to cytomegalovirus in patients receiving immunosuppressive therapy

Employing the techniques of complement-fixation (CF), immunofluorescence (IF), and in vitro lymphocyte transformation (LTF), the humoral antibody response and cell-mediated immune (CMI) response to cytomegalovirus (CMV) were studied in the serum and peripheral blood lymphocytes in 19 normal children (controls) and 23 patients with renal disease who were receiving immunosuppressive therapy or undergoing hemodialysis. The LTF activity was determined by the whole blood microassay using two strains of CMV (AD-169 and Davis) and phytohemagglutinin (PHA). The antibody level responses to CMV in different groups of subjects were generally similar. The LTF response to PHA as evidenced by delta cpm activity was moderately depressed in immunosuppressed and hemodialyzed subjects compared to the response observed in the controls. The mean delta cpm activities in response to AD-169 and Davis strains of CMV in seropositive immunosuppressed patients were about one-fifth and one-third lower respectively than those of seropositive normal controls. These observations suggest that an impairment of CMV specific cellular immunity may be an important mechanism underlying the increased susceptibility to CMV infections in patients with chronic renal disease who receive immunosuppressive therapy.