Amyloid Positive Hydrocephalus: A Hydrocephalic Variant of Alzheimer's Disease?

BACKGROUND

Alzheimer's disease (AD) and normal pressure hydrocephalus (NPH) commonly coexist.

OBJECTIVE

We aimed to characterize an overlapping syndrome of AD and NPH that presents with gait disturbance, ventriculomegaly on magnetic resonance imaging, and significant amyloid deposition on positron emission tomography (PET).

METHODS

Of 114 patients who underwent cerebrospinal fluid (CSF) drainage for a possible diagnosis of NPH between 2015 and 2020 in Samsung Medical Center, we identified 24 patients (21.1%) with the NPH patients with amyloid deposition on PET, which we referred to as hydrocephalic AD in this study. We compared their clinical and imaging findings with those of 123 typical AD without hydrocephalic signs/symptoms. We also investigated the frequency and potential predictors of the tap test response in hydrocephalic AD.

RESULTS

Evans' index was 0.36±0.03, and a disproportionately enlarged subarachnoid space was present in 54.2% of the hydrocephalic AD patients. The mean age (75.2±7.3 years) and the APOE4 frequency (68.2%) did not differ from those of AD controls. However, the hydrocephalic AD patients showed better memory and language performance, and a thinner cingulate cortex. About 42% of the hydrocephalic AD patients responded to the tap test, of whom seven underwent shunt surgery. Cognition did not improve, whereas gait improved after shunt surgery in all.

CONCLUSION

Hydrocephalic AD has different neuropsychological and imaging characteristics from typical AD. Future studies are warranted to further investigate the effect of CSF removal on their clinical course and to elucidate the pathophysiological interaction between amyloid and NPH.

Exploratory Analysis of Behavioral Impulsivity, Pro-inflammatory Cytokines, and Resting-State Frontal EEG Activity Associated With Non-suicidal Self-Injury in Patients With Mood Disorder

Introduction: Non-suicidal self-injury (NSSI) is a rapidly increasing mental health problem that requires more clinical attention. In this study, we aimed to explore the biobehavioral markers of NSSI in participants with mood disorders. Methods: A total of 45 participants with mood disorders (bipolar I, II, and major depressive disorder) were included in the study. Behavioral impulsivity was measured using the immediate memory task (IMT)/delayed memory task (DMT) and the go-no-go (GNG) tests. Plasma levels of tumor necrosis factor-α (TNF-α), interleukin 1 beta (IL-1 β), and interleukin 6 (IL-6) and resting-state quantitative electroencephalography (qEEG) were measured. Results: The NSSI group had shorter GNG reaction time (GNG-RT) and higher TNF-α levels compared to the non-NSSI group. TNF-α was positively correlated with frontal theta power. In addition, GNG-RT showed a significant positive association with frontal alpha activity. Conclusion: NSSI in mood disorders was associated with increased behavioral impulsivity and greater inflammation. Increased pro-inflammatory cytokines were associated with frontal theta power. Increased inflammation might change major neurotransmitter metabolism, which eventually affects frontal function and decreases response inhibition. Further studies to explore their causal relationship are warranted.

Allogeneic Hematopoietic Cell Transplantation in Patients with Primary Immunodeficiencies in Korea: Eleven-Year Experience in a Single Center

PURPOSE

We aimed to report our single-center experience of allogeneic hematopoietic cell transplantation (HCT), which has been the only curative option for certain patients with lethal primary immunodeficiencies (PIDs).

METHODS

We summarized the results of HCT performed for patients with PIDs for 11 consecutive years from 2006 to 2016 at Samsung Medical Center, Seoul, Korea. Twenty-six patients with PIDs received HCT. Most had chronic granulomatous disease (42.3%), Wiskott Aldrich syndrome (15.4%), or severe combined immunodeficiency (11.5%).

RESULTS

Nine patients (34.6%) received HCT during the former half period and 17 patients (65.4%) during the latter half period. Donor types were categorized as: matched sibling donor (n = 5), unrelated donor (n = 17), and familial mismatched donor (FMMD) (n = 4). Unrelated HCT and FMMD transplantation were increasingly performed in the latter half period compared to the first (5 vs. 16, P = 0.034). Five patients experienced initial engraftment failure, but all of them were eventually engrafted after additional HCTs. The 3-year probability of overall survival was 72.0%. Seven patients (26.9%) died, and the causes of death were bacterial sepsis (n = 4), pneumonia (n = 1), chronic graft-versus-host disease (GVHD) (n = 1), and diffuse alveolar hemorrhage (n = 1). Two patients with bacterial sepsis and a patient with pneumonia also had chronic GVHD. Unrelated HCT and use of methotrexate were associated with poor outcome. Complete chimerism was attained in 85.0% at 1 year after HCT.

CONCLUSION

PID candidates have been increasingly identified for allogeneic HCT in Korea, and the majority of them could be cured by HCT. Establishment of a systematic registry of PID patients for HCT is needed.

Sarcopenia is associated with the risk of significant liver fibrosis in metabolically unhealthy subjects with chronic hepatitis B

BACKGROUND

Sarcopenia is significantly associated with the degree of liver fibrosis. This study investigated the influence of sarcopenia on liver fibrosis in individuals with chronic hepatitis B.

METHODS

Data from the Korean National Health and Nutrition Examination Surveys 2008-2011 were analysed. The sarcopenia index (total appendicular skeletal muscle mass [kg]/body mass index [kg/m² ]) was calculated using dual-energy X-ray absorptiometry. Sarcopenia was defined as the lowest quintile sarcopenia index value (cut-offs: 0.89 for men and 0.58 for women). The fibrotic burden was assessed using the nonalcoholic fatty liver disease fibrosis score and fibrosis-4 index. Significant fibrosis was defined as the highest nonalcoholic fatty liver disease fibrosis score quartile and a fibrosis-4 index ≥2.67.

RESULTS

Among the 506 respondents with chronic hepatitis B (258 men and 248 women), the nonalcoholic fatty liver disease fibrosis score and fibrosis-4 index identified sarcopenia and significant fibrosis in 126 (24.9%) and 217 (42.9%), respectively. Sarcopenia was significantly associated with significant fibrosis, regardless of the fibrosis prediction model used (all P < 0.05). When the study population was stratified according to metabolic factors, sarcopenia was specifically associated with an increased risk of significant fibrosis among subgroups with obesity, insulin resistance, metabolic syndrome and liver steatosis (odds ratio 2.37-3.57; all P < 0.05). An independent association between sarcopenia and significant fibrosis was identified after adjusting for other confounders (odds ratio 2.67-3.62 by the nonalcoholic fatty liver disease fibrosis score and 2.04-2.62 by the fibrosis-4 index; all P < 0.05).

CONCLUSIONS

Sarcopenia is associated with significant fibrosis in subjects with chronic hepatitis B, specifically those with obesity, insulin resistance, metabolic syndrome and liver steatosis.

Comparison of the Microtensile Bond Strength of a Polyetherketoneketone (PEKK) Tooth Post Cemented with Various Surface Treatments and Various Resin Cements

The aim of this in-vitro research was to evaluate the microtensile bond strength in the newly introduced PEKK tooth post with various surface treatments and resin cements. A fiberglass tooth post was included in order to compare it with PEKK as a possible post material. The microtensile bond strengths of the fiberglass post (FRC Postec Plus) and the PEKK post (Pekkton^®) were tested using three kinds of self-adhesive resin cements (G-CEM LinkAce, Multilink Speed, and RelyX U200) and one self-etching resin cement (PANAVIA F2.0). The surface treatments of the fiberglass posts were processed according to the manufacturer’s recommendations (F1, application of 37% phosphoric acid etching gel and silanization). For the PEKK post groups, various surface treatments were performed like no surface treatment (P1), sandblasting (P2), silica-coating and silanization (P3), and sandblasting with a composite primer (P4). In the surface treatment, PEKK posts with silica coating and silane treatment (P3) showed a significantly higher microtensile bond strength (mean MPa: 18.09, p < 0.05). The highest microtensile bond strength was shown when the PEKK posts were treated with a silica coating and silane treatment and cemented with RelyX U200 (mean MPa: 22.22). The PEKK posts with surface treatments of silica-coating and silanization or sandblasting displayed superior microtensile bond strengths (mean MPa: 18.09 and 16.25, respectively) compared to the conventional fiberglass posts (mean MPa: 14.93, p < 0.05).

Accuracy of several implant bite registration techniques: an in-vitro pilot study

PURPOSE

This study evaluated the accuracies of different bite registration techniques for implant-fixed prostheses using three dimensional file analysis.

MATERIALS AND METHODS

Implant fixtures were placed on the mandibular right second premolar, and the first and second molar in a polyurethane model. Aluwax (A), Pattern Resin (P), and Blu-Mousse (B) were used as the bite registration materials on the healing abutments (H) or temporary abutments (T). The groups were classified into HA, HP, HB, TA, TP, and TB according to each combination. The group using the bite impression coping was the BC group; impression taking and bite registration were performed simultaneously. After impression and bite taking, the scan bodies were connected to the lab analogs of the casts. These casts were scanned using a model scanner. The distances between two reference points in three-dimensional files were measured in each group. One-way ANOVA and Duncan's test were used at the 5% significance level.

RESULTS

The smallest distance discrepancy was observed in the TB group using the temporary abutments. The Blu-Mousse and HP groups showed the largest distance discrepancy. The TB and BC groups showed a lower distance discrepancy than the HP group (P=.001), and there was no significant difference between the groups using the temporary abutments and healing abutments (P>.05).

CONCLUSION

Although this study has limitations as an in-vitro investigation, the groups using the temporary abutments to hold the Blu-Mousse record and bite impression coping showed greater accuracy than the group using the healing abutments to hold the pattern resin record.

Preparation and Characterization of Resorbable Bacterial Cellulose Membranes Treated by Electron Beam Irradiation for Guided Bone Regeneration

Bacterial cellulose (BC) is an excellent biomaterial with many medical applications. In this study, resorbable BC membranes were prepared for guided bone regeneration (GBR) using an irradiation technique for applications in the dental field. Electron beam irradiation (EI) increases biodegradation by severing the glucose bonds of BC. BC membranes irradiated at 100 kGy or 300 kGy were used to determine optimal electron beam doses. Electron beam irradiated BC membranes (EI-BCMs) were evaluated by scanning electron microscopy (SEM), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, thermal gravimetric analysis (TGA), and using wet tensile strength measurements. In addition, in vitro cell studies were conducted in order to confirm the cytocompatibility of EI-BCMs. Cell viabilities of NIH3T3 cells on 100k and 300k EI-BCMs (100 kGy and 300 kGy irradiated BC membranes) were significantly greater than on NI-BCMs after 3 and 7 days (p < 0.05). Bone regeneration by EI-BCMs and their biodegradabilities were also evaluated using in vivo rat calvarial defect models for 4 and 8 weeks. Histometric results showed 100k EI-BCMs exhibited significantly larger new bone area (NBA; %) than 300k EI-BCMs at 8 weeks after implantation (p < 0.05). Mechanical, chemical, and biological analyses showed EI-BCMs effectively interacted with cells and promoted bone regeneration.

Increase in resting heart rate over 2 years predicts incidence of diabetes: A 10-year prospective study

OBJECTIVE

The association between resting heart rate (RHR) and the development of diabetes has yet to be fully elucidated, and the relationship between changes in RHR and incidence of diabetes also remains unclear. Our study aimed to investigate the association between changes in RHR over 2 years and the risk of diabetes.

METHODS

A total of 7416 adults without diabetes were included. All had participated in the Korean Genome and Epidemiology Study, a community-based, 10-year prospective study in which RHR was measured at baseline and 2 years later. Incident diabetes was defined as fasting blood glucose ≥126mg/dL, 2-h post-load glucose ≥200mg/dL during a 75-g oral glucose tolerance test or current use of diabetes medication. The relative risk of diabetes associated with the 2-year change in RHR was calculated using Cox models.

RESULTS

During the 10-year follow-up, 1444 (19.5%) developed diabetes. Compared with RHR increases <5 beats per minute (bpm) over 2 years, increases >10bpm were significantly associated with development of diabetes (adjusted hazard ratio: 1.31, 95% confidence interval: 1.06-1.60), even after adjusting for glycometabolic parameters and baseline RHR. This significant association was attenuated in people who exercised regularly (P=0.650), but remained significant in those not doing any regular exercise (P=0.010).

CONCLUSION

An increase in RHR over a 2-year follow-up period is significantly associated with a risk of diabetes, independently of baseline RHR and glycometabolic parameters. Further investigations into ways to control RHR as a potential preventative measure against the development of diabetes are now needed.

Identification of a novel HLA-C*03 variant allele, C*03:280 by sequence-based typing

The new allele, HLA-C*03:280 differs from C*03:04:01 by one nucleotide substitution at codon 35 (CGG→CAG).

Delayed Presentation of Catheter-related Subclavian Artery Pseudoaneurysm

Central venous catheterization is a common diagnostic and therapeutic procedure in modern clinical practice. Pseudoaneurysms of the subclavian artery are rare and usually occur immediately after the causative event, whether the cause was trauma or a medical procedure. Here, we report a case of a 71-year-old woman with delayed presentation of catheter-related subclavian pseudoaneurysm. The patient’s symptoms began two weeks after the initial catheterization, probably because of slow leakage of blood from the injured subclavian artery caused by incomplete compression of the puncture site and uremic coagulopathy. She was successfully treated with ultrasound-guided thrombin and angiography-guided histoacryl injection without stent insertion or surgery. Keywords: butyl 2-cyanacrylate; pseudoaneurysm; subclavian; thrombin.

Comparing kidney outcomes in type 2 diabetes treated with different sulphonylureas in real-life clinical practice

AIM

Although several sulphonylureas are widely used in type 2 diabetes (T2D), their differential impacts on long-term major kidney outcomes remain unclear. This study aimed to investigate the effects of the two most commonly prescribed sulphonylureas, glimepiride and gliclazide, on kidney outcomes in patients with T2D.

METHODS

A total of 4486 patients treated with either glimepiride or gliclazide for more than 2 years were followed for up to 5.5 years (median: 4.7 years). A propensity score based on baseline characteristics was used to match 1427 patients treated with glimepiride with 1427 gliclazide-treated patients; incidences of end-stage renal disease (ESRD) and sustained doubling of creatinine to>132.6 μmol/L (1.5mg/dL) were also compared.

RESULTS

In the matched cohort with 12,122 person-years of follow-up, there was no significant difference between groups in risk of ESRD [hazard ratio (HR): 0.57, 95% confidence interval (CI): 0.29-1.12] or doubling of creatinine (HR: 0.74, 95% CI: 0.44-1.26), although there was a trend towards higher risks in the glimepiride group. Subgroup analyses showed that, compared with glimepiride, gliclazide was associated with a lower risk of doubling of creatinine in patients with preserved renal function (glomerular filtration rate ≥ 60 mL/min/1.73 m(2), HR: 0.21, 95% CI: 0.04-0.99) and good glycaemic control (HbA1c < 7%, HR: 0.35, 95% CI: 0.14-0.86), and in older subjects (≥ 62 years, HR: 0.52, 95% CI: 0.27-0.99).

CONCLUSION

In a real-life setting, there was no significant difference in clinical outcomes of kidney disease for patients treated with glimepiride vs gliclazide. However, gliclazide appeared to protect against renal complication progression in certain populations.

A new HLA-A*30 allele, A*30:81, identified by sequence-based typing

The new allele, HLA-A*30:81, differs from A*30:01:01 by one nucleotide substitution at codon 272 (CTG→ATG).

Ligand-activated peroxisome proliferator-activated receptor-δ and -γ inhibit lipopolysaccharide-primed release of high mobility group box 1 through upregulation of SIRT1

Peroxisome proliferator-activated receptors (PPARs) inhibit lipopolysaccharide (LPS)-primed release of high mobility group box 1 (HMGB1), a late proinflammatory mediator, but the underlying molecular mechanism is not completely understood. In this study, we demonstrated that the inhibition of HMGB1 release by PPAR-δ and -γ is associated with the deacetylase activity of SIRT1. Ligand-activated PPAR-δ and -γ inhibited LPS-primed release of HMGB1, concomitant with elevation in SIRT1 expression and promoter activity. These effects were significantly reduced in the presence of small interfering (si)RNAs against PPAR, indicating that PPAR-δ and -γ are involved in both HMGB1 release and SIRT1 expression. In addition, modulation of SIRT1 expression and activity by siRNA or chemicals correspondingly influenced the effects of PPARs on HMGB1 release, suggesting a mechanism in which SIRT1 modulates HMGB1 release. Furthermore, we showed for the first time that HMGB1 acetylated in response to LPS or p300/CBP-associated factor (PCAF) is an effective substrate for SIRT1, and that deacetylation of HMGB1 is responsible for blockade of HMGB1 release in macrophages. Finally, acetylation of HMGB1 was elevated in mouse embryonic fibroblasts from SIRT1-knockout mice, whereas this increase was completely reversed by ectopic expression of SIRT1. These results indicate that PPAR-mediated upregulation of SIRT1 modulates the status of HMGB1 acetylation, which, in turn, has a critical role in the cellular response to inflammation through deacetylation-mediated regulation of HMGB1 release.

A novel PRF1 gene mutation in a fatal neonate case with type 2 familial hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) occurs in the primary form (genetic or familial) or secondary form (acquired). The familial form of HLH (FHL) is a potentially fatal autosomal recessive disorder that occurs because of constitutional defects in cell-mediated cytotoxicity. Here, we report a fatal neonatal case of type 2 FHL (FHL2) that involved a novel frameshift mutation. Clinically, the newborn presented with severe sepsis-like features and required mechanical ventilation and continuous venovenous hemodiafiltration. Flow cytometry analysis showed marked HLH and complete absence of intracytoplasmic perforin expression in cytotoxic cells; therefore, we performed molecular genetic analyses for PRF1 mutations, which showed that the patient had a compound heterozygous mutation in PRF1, that is, c.65delC (p.Pro22Argfs*2) and c.1090_1091delCT (p.Leu364Glufs*93). Clinical and genetic assessments for FHL are required for neonates with refractory fever and progressive multiple organ failure, particularly when there is no evidence of microbiological or metabolic cause.

The novel allele HLA-C*03:04:36 identified by sequence-based typing

The new allele, HLA-C*03:04:36, differs from C*03:04:01:01 by one nucleotide substitution at codon 207 (GGC→GGT).

Frequencies of 10 autosomal minor histocompatibility antigens in Korean population and estimated disparities in unrelated hematopoietic stem cell transplantation

Disparity of minor histocompatibility antigens (mHAs) is known to induce graft-versus-tumor and graft-versus-host disease reactions in stem cell transplantation. Not much information is available on genotypic and phenotypic distributions of the currently identified mHAs, especially in Korean population. Therefore, we report genotype and phenotype frequency analyses of 10 autosomal mHAs in 329 unrelated healthy Koreans using the Sequenom MassARRAY matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) system and polymerase chain reaction-sequence specific primers (PCR-SSP). Estimates of the probability of immunogenic mismatches between donor/recipient pairs were made from observed phenotypic frequencies. HA-1 was the most favorable mHA for clinical application with the highest disparity of 7.0%. Similar results were obtained in ACC-1. The Korean population can benefit the most in a setting of matched major histocompatibility complex (MHC)-restricted mHAs-mismatched unrelated hematopoietic stem cell transplantations with the disparity rate of 27.5% with eight hematopoietic mHAs. This is the first comprehensive report on the genotypic and phenotypic frequency distributions of human mHAs in the Korean population. It can contribute to not only donor selection before transplantation but also therapeutic approaches after transplantation. It is expected that mHA-based immunotherapy will lead to a new treatment modality tailored for patients at high risk of relapse following allogeneic hematopoietic cell transplantation.

Demethylation analysis of the FOXP3 locus shows quantitative defects of regulatory T cells in IPEX-like syndrome

Immune dysregulation, Polyendocrinopathy, Enteropathy X-linked (IPEX) syndrome is a unique example of primary immunodeficiency characterized by autoimmune manifestations due to defective regulatory T (Treg) cells, in the presence of FOXP3 mutations. However, autoimmune symptoms phenotypically resembling IPEX often occur in the absence of detectable FOXP3 mutations. The cause of this “IPEX-like” syndrome presently remains unclear.

To investigate whether a defect in Treg cells sustains the immunological dysregulation in IPEX-like patients, we measured the amount of peripheral Treg cells within the CD3⁺ T cells by analysing demethylation of the Treg cell-Specific-Demethylated-Region (TSDR) in the FOXP3 locus and demethylation of the T cell-Specific-Demethylated-Region (TLSDR) in the CD3 locus, highly specific markers for stable Treg cells and overall T cells, respectively.

TSDR demethylation analysis, alone or normalized for the total T cells, showed that the amount of peripheral Treg cells in a cohort of IPEX-like patients was significantly reduced, as compared to both healthy subjects and unrelated disease controls. This reduction could not be displayed by flow cytometric analysis, showing highly variable percentages of FOXP3⁺ and CD25⁺FOXP3⁺ T cells. These data provide evidence that a quantitative defect of Treg cells could be considered a common biological hallmark of IPEX-like syndrome. Since Treg cell suppressive function was not impaired, we propose that this reduction per se could sustain autoimmunity.

Reduction in glycated albumin can predict change in HbA1c: comparison of oral hypoglycaemic agent and insulin treatments

AIM

To investigate whether the change in glycated albumin 3 weeks after initiating anti-diabetes treatment (oral hypoglycaemic agent or insulin) could predict the corresponding change in HbA(1c) 3 months later in Korean patients with Type 2 diabetes.

METHODS

A total of 140 patients were enrolled into two groups: group I (insulin-based; n = 100) and group II (oral hypoglycaemic agent-based; n = 40). Both glycated albumin and HbA(1c) levels were measured as 'glucose control markers' during hospitalization. Glycated albumin was measured again at 3 weeks (first visit) after the initial measurement, and HbA(1c) was measured at 3 months (second visit) after the initial measurement.. The change in glucose control marker was defined as 100 × (follow-up glucose control marker--hospital glucose control marker)/hospital glucose control marker.

RESULTS

In both groups, the change in glycated albumin at the first visit and in HbA(1c) at the second visit showed a moderate linear relationship (r = 0.735; P < 0.01). In group II (r = 0.778; P < 0.01), a slightly stronger linear relationship was demonstrated than in group I (r = 0.738; P < 0.001); however, there was no statistically significant difference between the two groups. A correlation coefficient between the change in glycated albumin and HbA(1c) was not affected by sex, age, BMI, haemoglobin, serum creatinine or albumin.

CONCLUSION

The reduction in glycated albumin 3 weeks after the initiation of treatment corresponded with the reduction in HbA(1c) 3 months after starting treatment in both the group treated with a oral hypoglycaemic agent and the insulin-treated group of Korean patients with Type 2 diabetes.

A low-risk ZnT-8 allele (W325) for post-transplantation diabetes mellitus is protective against cyclosporin A-induced impairment of insulin secretion

SLC30A8 encodes the β-cell-specific zinc transporter-8 (ZnT-8) expressed in insulin secretory granules. The single-nucleotide polymorphism rs13266634 of SLC30A8 is associated with susceptibility to post-transplantation diabetes mellitus (PTDM). We tested the hypothesis that the polymorphic residue at position 325 of ZnT-8 determines the susceptibility to cyclosporin A (CsA) suppression of insulin secretion. INS (insulinoma)-1E cells expressing the W325 variant showed enhanced glucose-stimulated insulin secretion (GSIS) and were less sensitive to CsA suppression of GSIS. A reduced number of insulin granule fusion events accompanied the decrease in insulin secretion in CsA-treated cells expressing ZnT-8 R325; however, ZnT-8 W325-expressing cells exhibited resistance to the dampening of insulin granule fusion by CsA, and transported zinc ions into secretory vesicles more efficiently. Both tacrolimus and rapamycin caused similar suppression of GSIS in cells expressing ZnT-8 R325. However, cells expressing ZnT-8 W325 were resistant to tacrolimus, but not to rapamycin. The Down's syndrome candidate region-1 (DSCR1), an endogenous calcineurin inhibitor, overexpression and subsequent calcineurin inhibition significantly reduced GSIS in cells expressing the R325 but not the W325 variant, suggesting that differing susceptibility to CsA may be due to different interactions with calcineurin. These data suggest that the ZnT-8 W325 variant is protective against CsA-induced suppression of insulin secretion. Tolerance of ZnT-8 W325 to calcineurin activity may account for its protective effect in PTDM.

Effect of ABCA1 variant on atherogenic dyslipidaemia in patients with Type 2 diabetes treated with rosiglitazone

AIMS

To investigate the effect of two common ATP-binding cassette transporter 1 (ABCA1) polymorphisms (rs4149263 and rs2020927) on atherogenic dyslipidaemia in Korean Type 2 diabetic patients who were treated with rosiglitazone.

PATIENTS AND METHODS

Two hundred and fifty-six patients with Type 2 diabetes who had never previously received peroxisome proliferator-activated receptor gamma (PPAR-gamma) agonists or lipid-lowering treatment were treated with 4 mg of rosiglitazone daily for 12 weeks without any adjustment to their glucose-lowering regimen. The primary outcome was the change in atherogenic index of plasma (AIP), calculated as log [triglyceride (mmol/l)/high-density lipoprotein cholesterol (mmol/l)], before and after rosiglitazone treatment. The effect of rosiglitazone on the change in AIP was compared across the ABCA1 single nucleotide polymorphisms (SNPs) rs41429263 and rs2020927.

RESULTS

Before adjustment, the change in AIP at 12 weeks was significantly different across the rs4149263 genotypes [median (interquartile range): -0.05 (-0.21, 0.09) for TT; 0.02 (-0.09, 0.17) for TC; and 0.11 (0.03, 0.25) for CC; P = 0.003], but not across the rs2020927 [-0.04 (-0.18, 0.10) for TT; 0.03 (-0.17, 0.15) for TC; and -0.03 (-0.13, 0.10) for CC; P = 0.401]. After controlling for age, gender and duration of diabetes, the presence of the C-allele was significantly associated with an increase in AIP by 0.13 [95% confidence interval (CI), 0.04-0.21; P = 0.003]. This association did not change significantly when body mass index and pretreatment metabolic parameters were additionally controlled for (the change in AIP: 0.14; 95% CI, 0.04-0.24; P = 0.007).

CONCLUSIONS

The ABCA1 SNP rs4149263 may be associated with the change in atherogenic lipid profile in Type 2 diabetes treated with rosiglitazone.

The clinical and immunogenetic characteristics of adult-onset type 1 diabetes mellitus in Korea

Although the HLA class II alleles and immunological abnormalities are associated with type 1 diabetes mellitus (T1DM) in all racial groups, there are considerable variations in the genotypes and the prevalence of autoantibodies. In order to investigate the characteristics of the immunogenetic patterns and to use these as an early diagnostic tool and guideline for a therapeutic plan, we examined the clinical characteristics and the patterns of anti-GAD antibody (GADA), IA-2 antibody (IA-2A), HLA-DR and HLA-DQ in Korean adult-onset T1DM patients. Adult-onset patients had higher serum C-peptide levels than child-onset patients. In adult-onset patients, the prevalence of GADA and IA-2A were 59.5% and 15.3% respectively, and increased frequencies of HLADR4 and-DR9 were found. The frequencies of HLADQA1,-DQB1 and-DQ heterodimers were similar to those of the control, but child-onset patients had high frequencies of the HLA-DR3,-DR4,-DR9, DQA1*0301, DQA1*0501 and DQB1*0201 genotypes. In conclusion, Korean adult-onset T1DM patients had a lower prevalence of GADA, which was comparable to that found in Caucasian patients. The detection of GADA might help to predict the insulin dependency of adult-onset diabetes. Difference in the frequencies of diabetes associated with HLA type suggests that there might be a heterogeneity in the pathogenesis of diabetes according to the age of onset.

Phorbol ester up-regulates aldose reductase expression in A549 cells: a potential role for aldose reductase in cell cycle modulation

Over-expression of aldose reductase (AR) has been observed in many cancer cells. To clarify the role of AR in tumor cells, we investigated the pathways mediating expression of the AR gene induced by 12-O-tetradecanoylphorbol-13-acetate (TPA), a potent tumor promoter. In A549 human lung adenocarcinoma cells, TPA elicited a dose- and time-dependent increase in AR mRNA level with an elevated enzyme activity. The TPA-induced increase in mRNA level and promoter activity of the AR gene was significantly attenuated in the presence of an inhibitor of protein kinase C, tyrosine kinase, or nuclear factor kappaB (NF-kappaB). TPA augmented the NF-kappaB-dependent gene transcription, indicating the involvement of NF-kappaB in this regulation. Accumulation of TPA-treated cells in S phase was almost completely abolished in the presence of ethyl 1-benzyl-3-hydroxy-2(5H)-oxopyrrole-4-carboxylate, an AR inhibitor. Taken together, TPA augmented the promoter activity of the AR gene via the activation of protein kinase and NF-kappaB. The inhibition of AR may assist in the chemotherapy of malignant tumors by suppressing the rapid growth of cancer cells.

Dnmt3b, de novo DNA methyltransferase, interacts with SUMO-1 and Ubc9 through its N-terminal region and is subject to modification by SUMO-1

Dnmt3b, a DNA methyltransferase, is essential for mammalian development potentially through its transcription repression activity. To comprehend the underlying regulatory mechanism of Dnmt3b, we isolated small ubiquitin-like modifier 1 (SUMO-1) and Ubc9 as Dnmt3b-interacting proteins using yeast two-hybrid screens. Deletion analysis and colocalization experiment demonstrated that Dnmt3b interacts with SUMO-1 and Ubc9 at its N-terminal region. We also confirmed the modification of Dnmt3b by SUMO-1 in vivo. These results suggest that sumoylation may constitute a regulation mechanism of Dnmt3b in vivo.

An enzyme hydrolyzing methylated inhibitors of nitric oxide synthase is present in circulating human red blood cells

N(G),N(G)-dimethyl-L-arginine (asymmetric dimethylarginine or ADMA) and N(G)-monomethyl-L-arginine (L-NMMA) are post-translationally synthesized amino acids of nuclear proteins. Upon release during protein turnover, they are not used in protein synthesis, but are excreted or metabolized by dimethylarginine dimethylaminohydrolase (DDAH) found in many tissues. DDAH is present in monocytic and polynuclear cells of blood, but no report has appeared of its presence in red blood cells (RBCs). Because methylated arginines can inhibit nitric oxide synthase (NOS) and elevations are reported in several diseases, we explored whether RBCs express this enzyme. DDAH is present in RBCs as supported by hydrolysis of both ADMA and L-NMMA, but not symmetric dimethylarginine, and by immunoprecipitation/Westem blot using a specific monoclonal antibody to human DDAH. In a pilot study of end-stage renal disease (ESRD) patients, RBC DDAH activity with ADMA as substrate correlated inversely with age (p = 0.005) and enzyme activities were higher in patients with greater diastolic blood pressure drops during hemodialysis (p = 0.02). Similar correlations were found with white cell DDAH activity. Thus, human RBCs can hydrolyze methylated arginines. These findings indicate the RBC could be used to assess the status of DDAH in various disease states.

Implications for the role of endogenous nitric oxide inhibitors in hemodialysis hypotension

Hypotensive episodes during hemodialysis in patients with end-stage renal disease in the absence of inadequate maintenance of the plasma volume, pre-existence of cardiovascular disease, or autonomic nervous system dysfunction is accompanied by increase in the plasma concentrations of the end-products of nitric oxide metabolism, above the levels expected based on the reduction of urea. Factors that can influence the synthesis of nitric oxide or the regulation of the effects of this free radical in patients with chronic renal failure are reviewed. Convergence of these factors and their interactions during the hemodialysis procedure are discussed as the basis for the generation of excessive amounts of nitric oxide that serves as an important contributing factor in the development of symptomatic hypotension.

Finger reconstruction with a free neurovascular wrap-around flap from the big toe

From 1983 to 1998, 16 cases of finger reconstruction with a free neurovascular wrap-around flap from the big toe were treated. Fourteen cases were successful, and two cases failed. The authors reviewed these cases on the average of about 38 months after surgery. Pinch power was 51 percent of the unaffected normal hand, and two-point discrimination was 7.6 mm. The mean resorption of the grafted bone was 13 percent in width and 9 percent in length. There were no complications such as fracture of the grafted bone, nonunion, and pulp dislodgement. This procedure provided length, stability, and adequate sensibility for a functional pinch and grasp. Sensory return to the wrap-around flap on the thumb was often greater than for the same area on the opposite foot. The donor site of the wrap-around flap was acceptable, both aesthetically and functionally, and allowed the wearing of open-toed shoes by young women. Finger reconstruction with a wrap-around flap from the big toe yielded excellent cosmetic and functional results in cases involving amputation at the level of the metacarpophalangealjoints or distal to it. In addition, this procedure was an excellent choice for treatment in cases involving avulsion injuries of the fingers and reconstruction of soft-tissue defects after tumor excision.

Role of Nitric Oxide Synthase in Collagen–Platelet Interaction: Involvement of Platelet Nonintegrin Collagen Receptor Nitrotyrosylation

Platelets possess the endothelial isoform of nitric oxide synthase (eNOS), which plays an important role in platelet function. Other laboratories, including ours, have reported that nitric oxide (NO) is released upon exposure of platelets to collagen, but the mechanism of the interaction is not yet established. The objective of this study is to examine the possible role of nonintegrin receptor nitrotyrosylation on collagen-induced platelet aggregation. Results of the study show that two platelet proteins with M(r) of 65- and 23-kDa proteins are nitrotyrosylated in a time-dependent manner after the addition of type I collagen. The M(r) 65-kDa protein is identified as the platelet receptor for type I collagen. The recombinant protein of the platelet receptor for type I collagen can also be nitrotyrosylated. The nitrotyrosylated recombinant protein loses its ability to inhibit type I collagen-induced platelet aggregation. In addition, the polyclonal anti-65 kDa immunoprecipitates eNOS suggesting that the platelet nonintegrin receptor for type I collagen is closely linked to the eNOS. These results demonstrate that the inhibitory effect of NO on collagen-induced platelet aggregation may be mediated by the nitrotyrosylation of the 65-kDa receptor.

Reversible sequestration of nitric oxide by hemoglobin during hemodialysis in end-stage renal disease

BACKGROUND

During hemodialysis, patients whose plasma concentrations of nitric oxide (NO) products increase reportedly experience hypotension. Therefore, whether NO bound to hemoglobin (Hb) could contribute to various clinical and laboratory changes during hemodialysis was explored in patients with end-stage renal disease (ESRD).

METHODS

Ten patients were studied during 3 hemodialysis treatments with samples of blood analyzed for RBC nitrosyl Hb (HbNO), L-arginine, asymmetric dimethylarginine (ADMA), plasma nitrite+nitrate (NOx), and buffy coat NO synthase (NOS) activities.

RESULTS

HbNO before and during hemodialysis varied considerably. Those with higher predialysis levels had lower HbNO values during dialysis, whereas HbNO levels in those with lower levels before dialysis increased. Plasma NOx did not correlate with HbNO, but change in HbNO in the first hour and change in NOx in the first 2 hours correlated with drop in diastolic and systolic blood pressures (BP), respectively. HbNO concentrations increased in patients with >35% drop in systolic BP, whereas in those with <35% drop, HbNO concentrations decreased. HbNO levels adjusted by the hematocrit showed a drop in HbNO for the <35% group and a >3-fold increase in the >35% group. HbNO levels were higher in men than in women, and levels and changes correlated with the hematocrit, skin temperatures, plasma ADMA, arginine, and buffy coat NOS.

CONCLUSIONS

In patients with >35% drop in systolic BP, NO was scavenged by Hb in the circulating RBCs, undoubtedly attenuating the degree of hypotension. These data indicate that the amount of NO that is scavenged or released by Hb in the circulating RBCS during dialysis is highly variable and reversible. Various predialysis factors relate to the concentration of HbNO before and during dialysis, which in turn influence clinical findings that occur during the interdialytic period.

Complications of operative treatment for mallet fractures of the distal phalanx

Twenty-four of 59 (41%) surgically treated mallet fractures developed postoperative complications. The most common complication was marginal skin necrosis on the dorsal aspect of the distal phalanx, but recurrent extension lag, permanent nail deformities, transient infections along the Kirschner wires and pull-out steel wires and osteomyelitis were also observed.

Schwannomas of the upper extremity

This study presented the clinical characteristics, MRI features and postoperative results of 20 schwannomas in the arms of 13 patients. Twelve tumours had a positive Tinel's sign, one caused weakness of the wrist and another in Guyon's canal caused hypothenar muscle atrophy. Of the nine cases which underwent magnetic resonance imaging preoperatively, six were correctly diagnosed as schwannomas. All masses were excised using microsurgical techniques and two transient neurological complications occurred.

Role of the recombinant protein of the platelet receptor for type I collagen in the release of nitric oxide during platelet aggregation

Nitric oxide plays an important role in platelet function and platelets possess the endothelial isoform of nitric oxide synthase. Several reports have indicated that nitric oxide is released upon exposure of platelets to collagen. We have reported that a non-integrin platelet protein of 65 kDa is a receptor for type I collagen. By direct measurement of NO release from washed human platelets suspended in Tyrode buffer with a ISO-NO Mark II, World Precision Instruments, Sarasota, FL, USA, p30 sensor, type I collagen, but not ADP and epinephrine, induces the release of NO in a time-dependent manner. The production of NO is inhibited either by preincubation of type I collagen with the platelet type I collagen receptor recombinant protein or by preincubation of platelets with the antibody to the receptor protein, the anti-65 antibody. However, preincubation of platelets with anti-P-selectin and anti-glycoprotein IIb/IIIa did not affect the release of NO by platelets. These results suggest that the 65 kDa platelet receptor for type I collagen is specifically linked to the generation of NO, and that the 65 kDa platelet receptor for type I collagen plays an important new role in platelet function.

Endoscopic carpal tunnel release in patients receiving long-term hemodialysis

This study evaluated the clinical results of endoscopic carpal tunnel release in carpal tunnel syndrome caused by long-term hemodialysis and compared the results with that of idiopathic carpal tunnel syndrome. Operations were done in 32 patients (60 hands) with idiopathic carpal tunnel syndrome and in eight patients (15 hands) with carpal tunnel syndrome resulting from long-term hemodialysis. There was no significant difference in findings of preoperative evaluations and postoperative clinical results between the two groups, except for a difference with the patient satisfaction score with surgery on a visual analogue scale. The mean satisfaction score was 9.0 at 6 months, 9.3 at 1 year, and 9.5 at the 2-year followup in the group of patients with idiopathic carpal tunnel syndrome. However, in the group of patients with carpal tunnel syndrome resulting from long-term hemodialysis, the mean satisfaction score was 8.5 at 6 months, 8.2 at 1 year, and 6.5 at the 2-year followup. The score began to decrease at an average of 17.2 months after surgery. Long-term hemodialysis related carpal tunnel syndrome showed satisfactory short-term clinical results until approximately 1.5 years after the operation. After that time, the symptoms tended to deteriorate in 50% of the patients who received hemodialysis continuously.

Normal circulating adult human red blood cells contain inactive NOS proteins

Human red blood cells (RBCs) are considered to play a significant role in both blood pressure (BP) regulation and tissue oxygenation, because they can bind as well as release previously bound nitric oxide (NO) from hemoglobin (Hb) and other intracellular components. Two reports indicate that the human RBC possesses nitric oxide synthase (NOS) activity-by the accumulation of nitrite across a membraned chamber in one and by the hydrolysis of labeled L-arginine, presumably to labeled L-citrulline, in the other. Furthermore, NOS proteins have been identified by immunoblot in RBCs. If true, the presence of NOS activity would convert the human RBC to a donor with limited ability to bind exogenously generated NO. In considering the importance of the question of the presence or not of NO synthetic capacity of this cell in BP regulation and tissue perfusion, whether human RBCs are, indeed, able to hydrolyze L-arginine to L-citrulline, the coproduct of NO was explored. RBC samples collected from control subjects were assayed for NOS activity by incubation of homogenized cellular fractions with labeled tritiated L-arginine in the presence of 0.5 mmol/L NADPH. By this method, the amino acid coproduct of NO, tritiated L-citrulline, would be recovered in the supernatant after removal of unused substrate by cationic resin treatment. At first, activity appeared to be present in the RBC supernatant but not in the pellet. However, activity was not suppressed by known inhibitors of NOS, whereas activity was suppressed by norvaline, an inhibitor of arginase activity with no known effect on NOS. By contrast, RBC arginase activity was not inhibited by N(omega)-nitro-L-arginine, NG-methyl-L-arginine, or aminoguanidine, known inhibitors of NOS, but was inhibited by norvaline. The label recovered by thin-layer chromatography was determined not to be tritiated L-citrulline but was instead tritiated L-ornithine, the product of arginase activity. Thus the enzymatic hydrolysis of L-arginine was not caused by NOS but was a result of the action of the enzyme arginase, which abounds in this cell. However, proteins interacting with antibodies to the endothelial and inducible isoforms of NOS were detected in human RBCs by immunoblot. Together, these findings indicate that human RBCs collected from normal adult individuals possess proteins that react with monoclonal antibodies to the Inducible and endothelial isoforms of NOS, but the proteins are without catalytic activity.

Biphasic changes in nitric oxide generation in hemodialyzed patients with end-stage renal disease treated with recombinant human erythropoietin

BACKGROUND

Use of recombinant human erythropoietin (rHuEpo) in patients with end-stage renal disease (ESRD) improves anemia and reduces the need for blood transfusions. However, one third of patients on rHuEpo develop hypertension, aggravation of preexistent hypertension, or other complications. Nitric oxide (NO) plays a role in blood pressure (BP) regulation. Whether rHuEpo treatment in ESRD is accompanied by alterations in NO production was explored in patients undergoing hemodialysis.

METHODS

Of 121 consecutive patients in a hemodialysis clinic, 107 were treated with rHuEpo and 14 were untreated. Plasma was collected before and after hemodialysis for quantification of nitrite and nitrate (NOx). Findings were correlated with various routinely monitored parameters.

RESULTS

Predialysis NOx levels were lower in the treated than the untreated group; postdialysis NOx levels were virtually the same. Thus, the change was less in the treated group. Urea reduction ratios (URR) and ultrafiltrate volumes were similar. The mean predialysis systolic BP was higher in the treated group than in the untreated group. The dose of rHuEpo did not correlate with the plasma NOx or the predialysis BPs. No correlation was found between NOx levels and Hb or gender. Of the 107 treated patients, 12 had an increased postdialysis NOx without differences in ultrafiltrate volumes or URR. This group had higher total serum calcium levels, faster pulses, and greater BP reductions than other treated patients. No difference was found in the use of calcium-channel blockers and serum phosphorus and intact parathyroid hormone concentrations did not differ significantly among these groups.

CONCLUSIONS

Intermittently hemodialyzed ESRD patients treated with rHuEpo accumulate less NOx in the plasma before dialysis but generate more NOx during dialysis than untreated patients. About 11% of treated patients generated excessive amounts of NOx, thereby maintaining plasma concentrations at the predialysis level or higher. This group experienced significant hemodynamic consequences characteristic of the excessive action of NO.

The role of radiotherapy in the treatment of aggressive fibromatosis

Aggressive fibromatosis is a rare benign soft tissue tumor that is difficult to cure because of its infiltrative nature and high tendency to recur locally. The authors retrospectively analyzed 20 patients with histologically-confirmed fibromatosis. All patients underwent surgery with a wide or marginal margin. Five (25%) cases with histologically-negative margins had recurred. External beam radiotherapy was administered to patients whose margins were positive or who had local recurrence. However, out of concern for safety, radiotherapy was not given to two babies and a reproductive-aged woman. The average dose was 5,020 cGy. During the follow-up (mean 32.6 months), all the patients undergoing radiotherapy showed no evidence of local recurrence. A wide local excision has traditionally been the treatment of choice. However, postoperative radiotherapy could be an effective measure for preventing local recurrence in patients with a histologically-positive surgical margin and recurrence independent of any signs of relapse.

Ideal concentration of growth factors in rabbit's flexor tendon culture

Growth factors have the ability to stimulate matrix synthesis and cell proliferation in rabbit flexor tendon. Maximal stimulation effects of growth factors have a wide variation. It depends upon the different anatomic sites of the tendon segment, the kinds of growth factor, the concentration of growth factors, and the time sequence. Since proliferation was an early component of intrinsic tendon healing, we investigated the short-term dose response to four different growth factors on in vitro rabbit's tendon culture. We evaluated the effects according to the various concentrations of recombinant human insulin-like growth factor 1 (IGF), recombinant human epidermal growth factor (EGF), fibroblast growth factor (FGF), and recombinant human platelet-derived growth factor-BB (PDGF). Fetal calf serum was the most potent stimulator of cell proliferation and protein synthesis in in vitro rabbit's tendon culture. Matrix synthesis and cell proliferation were stimulated dose-dependently by IGF between the doses of 50 and 150 ng/ml. The maximum mitogenic effect of EGF was observed at the concentration of 100 ng/ml (1.3 times more than the media-only control culture). The rabbit's tendon responded significantly dose-dependently to PDGF, whereas there was no significant response to FGF.

Hemodialysis hypotension: interaction of inhibitors, iNOS, and the interdialytic period

Hypotension during hemodialysis in end-stage renal disease (ESRD) not explained by excessive ultrafiltration has been linked to an apparent increase in the synthesis of nitric oxide (NO). The authors tested whether the induction of NO synthase (iNOS) by cytokines or differences in the concentrations of inhibitors of NOS or both could account for variability in the amount of NO synthesized during hemodialysis. Plasma levels of an inhibitor of NOS, asymmetric dimethylarginine (ADMA), L-arginine, the substrate for NOS, the end-products N02+N03, iNOS activity in circulating buffy coat cells, and their interdialytic changes were measured in 10 patients during three treatments. Predialysis (0') levels of ADMA were markedly elevated with a mean of 0.008+/-0.002 micromol/mL of deproteinized plasma, compared to controls where ADMA is present in trace amounts. ADMA levels from 30 minutes to the end of dialysis correlated directly with the drop in blood pressure (BP), with levels being much higher in patients with severe hypotension. Postdialysis ADMA levels correlated directly with the 0' systolic BP and the drop in BP at the next dialysis treatment. NOS activity was detected in two thirds of the predialysis buffy coat samples, and appeared to increase as dialysis progressed. 0' iNOS activity correlated inversely with the 0' BP, but activities did not differ based on percent drop in BP. iNOS activity in the 0' samples correlated inversely with the time since the last dialysis, reflecting the greater accumulation of dialyzable inhibitors of NOS as the interval is prolonged. The interdialytic change in iNOS activity correlated inversely with the drop in BP. The isoform detected immunochemically in the buffy coat samples had an Mr of 130 kDa and was reactive with antihuman iNOS. Thus, iNOS is already induced in the cells of the buffy coat in many intermittently hemodialyzed ESRD subjects, but its expression may be masked by inhibitors. After 60 minutes of dialysis (too brief a time for the de novo induction of iNOS,) the appearance of or increase in iNOS activity suggests that an inhibitor had been removed. Because ADMA levels are associated with higher predialysis systolic BPs that result in a greater severity of hypotension, reduction in ADMA concentrations would appear to play a major role in the resumption of NO synthesis by various isoforms.

Korean Nationwide Surveillance of Antimicrobial Resistance of bacteria in 1997

Antimicrobial-resistant bacteria are known to be prevalent in tertiary-care hospitals in Korea. Twenty hospitals participated to this surveillance to determine the nationwide prevalence of resistance bacteria in 1997. Seven per cent and 26% of Escherichia coli and Klebsiella pneumoniae were resistant to 3rd-generation cephalosporin. Increased resistance rates, 19% of Acinetobacter baumannii to ampicillin/sulbactam, and 17% of Pseudomonas aeruginoa to imipenem, were noted. The resistance rate to fluoroquinolone rose to 24% in E. coli, 56% in A. baumannii and 42% in P. aeruginosa. Mean resistance rates were similar in all hospital groups: about 17% of P. aeruginosa to imipenem, 50% of Haemophilus influenzae to ampicillin, 70% of Staphylococcus aureus to methicillin, and 70% of pneumococci to penicillin. In conclusion, nosocomial pathogens and problem resistant organisms are prevalent in smaller hospitals too, indicating nosocomial spread is a significant cause of the increasing prevalence of resistant bacteria in Korea.

Lipoprotein(a) and apolipoprotein(a) phenotypes in patients with end-stage renal disease

OBJECTIVE

To evaluate the distribution pattern of apolipoprotein(a) [Apo(a)] phenotypes in Koreans and the effect of dialysis modality on serum lipoprotein(a) [Lp(a)] concentration according to apo(a) phenotype in patients with end-stage renal disease (ESRD).

DESIGN

Cross-sectional study.

SETTING

A university hospital.

PARTICIPANTS

153 normal controls, 99 hemodialysis (HD) patients and 82 continuous ambulatory peritoneal dialysis (CAPD) patients.

MAIN OUTCOME MEASURES

Fasting serum Lp(a), lipids, and apo(a) phenotypes were measured.

RESULTS

The frequencies of the subjects with apo(a) phenotypes of high-molecular weight only, including S3, S4, or S5 or null type were 95.4% of control, 100% of HD patients, and 95.1% of CAPD patients. The frequent apo(a) phenotypes in Koreans consisted of S4, S4S5, S5, and S5S5 isoforms. Significant difference was found in serum Lp(a) concentration among controls and HD and CAPD patients [median (Interquartile range): 0.05 g/L, (0.01-0.19); 0.19 g/L, (0.10-0.35); 0.63 g/L, (0.28-0.90), p < 0.001]. Lp(a) levels in CAPD patients were significantly higher than in HD patients for all four common apo(a) isoforms found in Korean subjects. CAPD patients had higher total and LDL cholesterol levels, and higher ApoB levels than HD patients. Significant differences were found in serum albumin levels between controls and HD and CAPD patients (44 +/- 3 g/L, 40 +/- 4 g/L, 32 +/- 7 g/L, respectively, p < 0.05). There were significant inverse correlations between serum albumin and Lp(a) (r = -0.33, p < 0.01), total cholesterol (r = -0.31, p < 0.01), LDL (r = -0.39, p < 0.01) or ApoB (r = -0.35, p < 0.01) in ESRD patients. A significant positive correlation was found between serum albumin and ApoA1 (r = 0.24, p < 0.01).

CONCLUSION

These findings indicate that Koreans have mainly high molecular weight apo(a) phenotypes and serum Lp(a) is elevated in CAPD patients compared to HD patients for common apo(a) phenotypes, which may contribute to the frequent cardiovascular mortality in CAPD patients.

Hypotension during hemodialysis: role for nitric oxide

Hypotensive episodes during hemodialysis are a frequent complication in patients with end-stage renal disease. The possibility that nitric oxide (NO), a major regulator of cardiovascular hemodynamics, could be a factor was explored. Pre and postdialysis plasma samples from 17 hemodialysis patients were analyzed for the stable end products of NO,nitrite + nitrate (NO2 + NO3), by the Greiss method. Predialysis NO2 + NO3 levels were significantly higher in end-stage renal disease than in nine age-matched controls (44.08 +/- standard error of mean 5.74 versus 18.67 +/- 3.56 uM, P = 0.017). In more than half of the patients, postdialysis values dropped markedly, whereas in others the value change was far less; several rose above predialysis values. Depending on the nitrite + nitrate reduction ratio (pre minus postdialysis NO2 + NO3 divided by the predialysis value) patients were separated into two groups, A (n = 9 where nitrate + nitrate reduction ratio was > 0.5 and B (n = 8 where nitrate + nitrate reduction ratio was < 0.5). Whereas the mean predialysis NO2 + NO3 values between groups A and B did not differ significantly, postdialysis levels fell from a predialysis mean of 50 uM to 12 uM in group A but rose from 37 uM to 45 uM in group B. The difference between the postdialysis values of group A and group B was significant (P = 0.0264). In group B, mean systolic blood pressure dropped more than in group A, (57.8 mm Hg compared with 21.2 mm Hg, P = 0.0078). When measured by analysis of variance for repeated measures, skin and core temperatures and blood pressures were lower in group B than in group A. The volume of the ultrafiltrate was removed and dialysis duration and mean weight loss did not differ. Thus, in group B, apparently NO formation increased during hemodialysis exceeding the rate of removal or metabolism of the end products, whereas in group A, NO2 + NO3 removal or metabolism was without apparent increase in the formation of NO. The basis for this difference is unknown. Because vasodilation is a major effect of NO, the strong association of severe reduction in blood pressures and increased NO synthesis in subset B suggests a role for NO in hypotensive episodes during hemodialysis.

Involvement of phosphoprotein phosphatase 1 in collagen-platelet interaction

The binding of type I collagen to its receptor initiates platelet aggregation, but the relationship of the receptor to other signal transduction components is not yet established. Correlation of platelet aggregation and anti-type I collagen receptor antibody immunoprecipitation of type I collagen treated [32PO4]-labeled platelets showed that there are two phosphoproteins (M(r) 53 kDa and 21 kDa) that coprecipitated with the 65 kDa platelet type I collagen receptor. In the present investigation, we have identified one of the phosphoproteins. A soluble component the 100,000x g supernatant fraction of 53 kDa protein is recognized by polyclonal anti-PP1 antibody. The activity of the precipitated phosphatase is inhibited by okadaic acid and inhibitor 1, suggesting that it is protein phosphatase 1 (PP 1). Phosphorylation decreases PP 1 activity as was found with [32PO4]-phosphorylase b as the substrate. The immunocoprecipitation of the type-1 collagen receptor and PP 1 inot the result of cross reactivity of the anti-type I collagen receptor antibody with the PP I protein. These results indicate that the platelet type I collagen receptor, PP 1, and unidentified 21 kDa protein are in close association with the platelet type I collagen receptor upon the binding of type I collagen by the receptor.

Upregulation of nitric oxide synthase in cultured human keratinocytes after ultraviolet B and bradykinin

Ultraviolet B (UVB) irradiation of the skin has been reported to upregulate nitric oxide synthase (NOS) activity with enhancement of nitric oxide (NO) formation. Bradykinin, a known stimulator of NO production, is produced in the skin within minutes of UVB irradiation. The combined effect of UVB and bradykinin on NOS was therefore examined in a cultured human keratinocyte (KC) line. Activity was determined in KC homogenates by the recovery of [3H]L-citrulline using labeled L-arginine as the substrate in the presence of mM NADPH. Monoclonal antibodies to specific isoforms of NOS that cross-react with their human counterparts were used to determine the isoform(s) in control, UVB, bradykinin treated and UVB and bradykinin treated KC. Human KC express NOS activity which is lowest at confluence and highest during proliferation. UVB increased NOS activity when a set dose of irradiation was administered from 32.2-48.3 mJ/cm2 but was inhibitory after 64.4 and 80.5 mJ/cm2. Thirty min after 10(-6) M bradykinin, NOS activity nearly doubled followed by return of activity to control levels at 60 min. Activity after UVB and bradykinin was only slightly higher than that observed with bradykinin alone. Immunochemically, an isoform of M(r) 155 kDa was detected in control cells with the antibody for the constitutive brain enzyme, bNOS. Recovery of this isoform increased after UVB treatment as well as after bradykinin which was time dependent. When both stimulants were used, the recovery of the 155 kDa enzyme was markedly enhanced, unlike the enzyme activity findings. These data indicate that the expression of NOS activity under unstimulated conditions in human KC in culture is due to the constitutive NOS found in neuronal tissue, bNOS. The recovery of bNOS increased after UVB and after bradykinin while the combination of both resulted in the synergistic increase in bNOS protein with only a marginal further increase in NOS activity.

Postprandial lipoprotein responses in hypertriglyceridemic subjects with and without cardiovascular disease

Three groups of age- and weight-matched men (aged 40 to 70 years) without diabetes were studied: controls (n = 10), plasma triglycerides (TG) less than 180 mg/dL and no cardiovascular disease (CVD); HTG-CVD (n = 11), hypertriglyceridemic (HTG) (TG > 240 mg/dL) without CVD; and HTG+CVD (n = 10), HTG (TG > 240 mg/dL) with documented CVD. HTG+CVD subjects had higher fasting and post-oral glucose tolerance test insulin levels than the other two groups, respectively. Very-low-density lipoprotein (VLDL)+chylomicrons (CMs), intermediate-density lipoprotein (IDL), low-density lipoprotein (LDL), and three high-density lipoprotein (HDL) subfractions (HDL-L, HDL-M, and HDL-D, from least to most dense) were isolated by gradient ultracentrifugation. Fasting lipoproteins were similar in HTG groups, except for higher VLDL lipid to apolipoprotein (apo) B ratios (P < .04) in the HTG+CVD group. Subjects were fed a high-fat mixed meal, and lipoprotein composition was determined at 3, 6, 9, and 12 hours postprandially. Postprandial responses of the core lipids (TG and cholesterol esters [CE]) in all of the lipoprotein subfractions were similar in the two HTG groups at each time point. However, both controls and HTG-CVD subjects had increases in HDL-M phospholipid (PL) at 9 and 12 hours with no change in HDL-D PL. The HTG+CVD group, on the other hand, had no increase in HDL-M PL and had a substantial reduction in HDL-D PL. These changes resulted in significant increases in HDL-M and HDL-D PL to apo A-I ratios in both controls and HTG-CVD subjects between 6 and 12 hours, whereas there was no increase seen in the HTG+CVD group. The HTG-CVD group also had a significantly greater increase in the VLDL+CM PL to apo B ratio (P = .038) at 3 hours than the HTG+CVD group. This diminished amount of surface lipid per VLDL particle may account for the late decrease in the HDL-D PL to apo A-I ratio seen in HTG+CVD patients. There were no other postprandial lipid or apolipoprotein differences between the two HTG groups. We conclude therefore that the major postprandial lipoprotein abnormality in these HTG+CVD patients was a failure to increase the PL content per particle in VLDL+CM, HDL-M, and HDL-D. This abnormality could prevent the usual increase in reverse cholesterol transport seen in postprandial plasma and therefore contribute to their increased incidence of CVD. The greater insulin resistance seen in these patients also appears to contribute significantly to their CVD.

Chronic exposure of rat fat cells to insulin enhances lipolysis and activation of partially purified hormone-sensitive lipase

The activity of adipose tissue hormone-sensitive lipase in animals with hyperinsulinemia has been reported to be increased compared with that in control animals. We examined whether this results from a direct effect of insulin on the tissue and whether it is accompanied by alteration in the regulation of lipolysis. When rat epididymal fat pads are incubated in culture medium with bovine serum albumin for 2-4 h with 2 ng/ml or 50 microU/ml of insulin, hormone-sensitive lipase activity in the postmicrosomal supernatant fraction after acid precipitation and activation with ATP-Mg2+ increases significantly compared with preparations from tissues incubated with the vehicle. The specific activities of hormone-sensitive lipase in sonicates of adipocytes after primary culture with insulin at concentrations from 10 to 4000 ng/ml (250 microU to 100 mU/ml) increase in an insulin-dose-related manner. Lipolysis in response to 10(-7) M isoproterenol also increases in an insulin-dose-dependent manner. Enhancement of isoproterenol-mediated lipolysis is not attributable to a difference in the triglyceride content of the cells. Lipolysis caused by the beta-agonist could be completely blocked by the simultaneous presence of insulin in both control and insulin-treated cells reflecting normal responsiveness of both types of cells to the acute effect of insulin. Although an increase in lipolysis is seen with norepinephrine and growth hormone after insulin treatment, other lipolytic agents such as ACTH, thyrotropin, and glucagon evoke similar responses in insulin-treated and control cells. The simultaneous presence of growth hormone and insulin during the 16-h culture results in additive effects on the subsequent response of the cells to 10(-7) M isoproterenol compared with the responses of the cells cultured with each hormone alone. beta-Agonist-mediated cAMP accumulation in the presence of Ro-20.1724, a specific phosphodiesterase inhibitor, is significantly higher in cells cultured in the presence of insulin than in control cells. Forskolin (1-25 microM) increases the lipolytic responses of insulin-treated cells compared with control cells, but the maximal response of the insulin-treated cells to forskolin is lower than that to isoproterenol. We conclude that changes produced by chronic insulin treatment involve more than one site along the lipolytic cascade.