Urinary tract dilation classification system for predicting surgical management and urinary tract infection in neonates and young infants: a systematic review and meta-analysis

BACKGROUND

The urinary tract dilation classification system has recently been developed to ensure a unified approach to describe urinary tract dilation in neonates and young infants. However, the predictive value of this system for surgical intervention or urinary tract infection (UTI) has not yet been evaluated in a meta-analysis.

OBJECTIVE

This systematic review and meta-analysis aimed to evaluate the utility of a postnatal urinary tract dilation classification system for predicting surgical management or a UTI occurrence.

MATERIALS AND METHODS

As the urinary tract dilation classification system was introduced in 2014, we searched Embase and PubMed databases for studies published between January 2014 and December 2022. Original articles that reported surgical interventions or UTI episodes according to postnatal urinary tract dilation grades were included. The pooled odds ratio (OR) was calculated, using either the fixed-effects or random-effects model, given the lower urinary tract dilation grades as the base category. The quality of the included studies was evaluated using the Newcastle-Ottawa scale.

RESULTS

Of the 285 articles reviewed, eight (comprising 2,165 children) were included in the analysis. The studies were of medium-to-high quality. Pooled analysis demonstrated that urinary tract dilation P3 (combined OR, 21.41; 95% confidence interval [CI], 15.72-29.17) and urinary tract dilation P2-P3 (combined OR, 65.17; 95% CI, 33.08-128.38) were associated with surgical intervention. The urinary tract dilation P3 (combined OR, 2.11; 95% CI, 1.56-2.85) and urinary tract dilation P2-P3 (combined OR, 3.36; 95% CI, 2.43-4.63) were associated with UTI episodes.

CONCLUSION

The postnatal urinary tract dilation classification system is useful for predicting the need for surgical management and UTI episodes in infants with hydronephrosis.

Long-term outcomes and associated prognostic risk factors of childhood-onset lupus nephritis

Background

This study investigated the clinical characteristics and kidney outcomes of childhood-onset lupus nephritis (LN), and risk factors associated with prognosis.

Methods

We enrolled 216 patients with histologically diagnosed LN during childhood. The Korean Society of Pediatric Nephrology organized a retrospective cohort study of childhood-onset LN in 13 major pediatric nephrology centers in South Korea.

Results

The mean age at kidney biopsy was 13.2 ± 3.22 years. The main forms of presentation were nephrotic syndrome and/or hematuria in 152 patients (70.4%), and the most common histological finding was World Health Organization (WHO) class IV in 138 patients (63.9%), followed by WHO class III in 34 patients (15.7%). In the outcome analysis, the mean follow-up period of the patients was 7.8 ± 5.11 years. At last follow-up, 32 patients (14.8%) developed advanced chronic kidney disease (CKD). Male sex and failure to achieve remission at 12 months of treatment were significant risk factors for developing advanced CKD (hazard ratio of 2.57 and 2.29, respectively).

Conclusion

Our study demonstrated the clinical characteristics and long-term outcomes of patients with childhood-onset LN. Male sex and failure to achieve remission in the first year of treatment were predictive of advanced CKD. Therefore, prompt awareness and close monitoring of these high-risk patients are needed, which may further improve the prognosis of children with LN.

Genotype-phenotype correlation of X-linked Alport syndrome observed in both genders: a multicenter study in South Korea

The genotype-phenotype correlation of the X-linked Alport syndrome (XLAS) has been well elucidated in males, whereas it remains unclear in females. In this multicenter retrospective study, we analyzed the genotype-phenotype correlation in 216 Korean patients (male:female = 130:86) with XLAS between 2000 and 2021. The patients were divided into three groups according to their genotypes: the non-truncating group, the abnormal splicing group, and the truncating group. In male patients, approximately 60% developed kidney failure at the median age of 25.0 years, and kidney survival showed significant differences between the non-truncating and truncating groups (P < 0.001, hazard ratio (HR) 2.8) and splicing and truncating groups (P = 0.002, HR 3.1). Sensorineural hearing loss was detected in 65.1% of male patients, while hearing survival periods showed a highly significant difference between the non-truncating and truncating groups (P < 0.001, HR 5.1). In female patients, approximately 20% developed kidney failure at the median age of 50.2 years. The kidney survival was significantly different between the non-truncating and truncating groups (P = 0.006, HR 5.7). Our findings support the presence of genotype-phenotype correlation not only in male patients but also in female patients with XLAS.

Erratum: efficacy and tolerability of anticholinergics in korean children with overactive bladder: a multicenter retrospective study

[This corrects the article on p. 1550 in vol. 29, PMID: 25408588.].

Efficacy and tolerability of anticholinergics in Korean children with overactive bladder: a multicenter retrospective study

We investigated the efficacy and tolerability of various anticholinergics in Korean children with non-neurogenic overactive bladder (OAB). A total of 326 children (males:females= 157:169) aged under 18 yr (mean age 7.3±2.6 yr) who were diagnosed with OAB from 2008 to 2011 were retrospectively reviewed. The mean duration of OAB symptoms before anticholinergic treatment was 16.9±19.0 months. The mean duration of medication was 5.6±7.3 months. Urgency urinary incontinence episodes per week decreased from 1.9±3.1 to 0.4±1.5 times (P<0.001). The median voiding frequency during daytime was decreased from 9.2±5.4 to 6.3±4.2 times (P<0.001). According to 3-day voiding diaries, the maximum and average bladder capacity were increased from 145.5±66.9 to 196.8±80.3 mL and from 80.8±39.6 to 121.8±56.5 mL, respectively (P<0.001). On uroflowmetry, maximum flow rate was increased from 17.6±8.4 to 20.5±8.2 mL/sec (P<0.001). Adverse effects were reported in 14 (4.3%) children and six children (1.8%) discontinued medication due to adverse effects. Our results indicate that anticholinergics are effective to improve OAB symptoms and tolerability was acceptable without severe complications in children.

Renovascular hypertension treated by renal artery embolization

Renovascular hypertension is caused by narrowing of the arteries supplying the kidneys. There are several methods to treat renal artery stenosis, such as medications, percutaneous transluminal renal angioplasty, and atherosclerosis. A boy presented to our hospital with severe hypertension. Computed tomography angiogram revealed severe narrowing of the left renal artery and hypoplastic left kidney. Total renal artery embolizaton was performed to make a complete occlusion of the left renal artery. Follow-up renin and aldosterone levels were gradually decreased. The main advantage of renal artery embolization is that it is minimally invasive compared with extensive surgical procedures. Therefore, renal artery embolization should be considered as an alternative to surgical nephrectomy in pediatric patients with renovascular hypertension.

A nationwide epidemiological study of nocturnal enuresis in Korean adolescents and adults: population based cross sectional study

We performed a nationwide epidemiological study to evaluate the prevalence and characteristics of nocturnal enuresis (NE) in Korean adolescents and adults. A questionnaire was sent via e-mail to 51,073 people aged 16-40 yr by stratified sampling according to age, sex, and region among a 200,000 internet survey panel pool. The questionnaire included following information; presence or absence of NE, frequency of NE, possible risk factors for NE, self-esteem scale score and depression score results, and measures for the treatment of NE. Among the 2,117 responders, 54 (2.6%) had NE (≥1 enuretic episode within 6 months). Of 54 bedwetters, 9.3% wet ≥1 night per week and 20.5% wet ≥1 per month. The prevalence rates remained relatively stable with no apparent trend of reduction with age. The presence of sleep disturbance, family history, urgency, or urge incontinence increased the probability of NE episode significantly. The self-esteem score was lower (P=0.053) and the depression scale score was higher (P=0.003) in bedwetters compared with non-bedwetters. Overall 2.6% of Korean aged 16-40 yr have NE. The higher rate of urgency and urge incontinence in adolescent and adult enuretics suggests that bladder function has an important role in adolescent and adult NE.

Mechanical stimulation by ultrasound enhances chondrogenic differentiation of mesenchymal stem cells in a fibrin-hyaluronic acid hydrogel

Chondrogenic differentiation and cartilage tissue formation derived from stem cells are highly dependent on both biological and mechanical factors. This study investigated whether or not fibrin-hyaluronic acid (HA) coupled with low-intensity ultrasound (LIUS), a mechanical stimulation, produces an additive or synergistic effect on the chondrogenesis of rabbit mesenchymal stem cells (MSCs) derived from bone marrow. For the purpose of comparison, rabbit MSCs were first cultured in fibrin-HA or alginate hydrogels, and then subjected to chondrogenic differentiation in chondrogenic-defined medium for 4 weeks in the presence of either transforming growth factor-beta3 (TGF-β3) (10 ng/mL) or LIUS treatment (1.0 MHz and 200 mW/cm(2) ). The resulting samples were evaluated at 1 and 4 weeks by histological observation, chemical assays, and mechanical analysis. The fibrin-HA hydrogel was found to be more efficient than alginate in promoting chondrogenesis of the MSCs by producing a larger amount of sulfated glycosaminoglycans (GAGs) and collagen, and engineered constructs made with the hydrogel demonstrated higher mechanical strength. At 4 weeks of tissue culture, the chondrogenesis of the MSCs in fibrin-HA were shown to be further enhanced by treatment with LIUS, as observed by analyses for the amounts of GAGs and collagen, and mechanical strength testing. In contrast, TGF-β3, a well-known chondrogenic inducer, showed a marginal additive effect in the amount of collagen only. These results revealed that LIUS further enhanced chondrogenesis of the MSCs cultured in fibrin-HA, in vitro, and suggested that the combination of fibrin-HA and LIUS is a useful tool in constructing high-quality cartilage tissues from MSCs.

Prevalence of primary immunodeficiency in Korea

This study represents the first epidemiological study based on the national registry of primary immunodeficiencies (PID) in Korea. Patient data were collected from 23 major hospitals. A total of 152 patients with PID (under 19 yr of age), who were observed from 2001 to 2005, have been entered in this registry. The period prevalence of PID in Korea in 2005 is 11.25 per million children. The following frequencies were found: antibody deficiencies, 53.3% (n = 81), phagocytic disorders, 28.9% (n = 44); combined immunodeficiencies, 13.2% (n = 20); and T cell deficiencies, 4.6% (n = 7). Congenital agammaglobulinemia (n = 21) and selective IgA deficiency (n = 21) were the most frequently reported antibody deficiency. Other reported deficiencies were common variable immunodeficiencies (n = 16), X-linked agammaglobulinemia (n = 15), IgG subclass deficiency (n = 4). Phagocytic disorder was mostly chronic granulomatous disease. A small number of patients with Wiskott-Aldrich syndrome, hyper-IgE syndrome, and severe combined immunodeficiency were also registered. Overall, the most common first manifestation was pneumonia. This study provides data that permit a more accurate estimation PID patients in Korea.

Characteristics of patients who visit the emergency department with self-inflicted injury

During visits to emergency medical facilities, the primary care of and risk identification for individuals who have attempted suicide is considered an important element in suicide prevention. With the ultimate goal of helping to prevent suicide, the aim of the present study was to determine the characteristics of patients with self-inflicted injuries who presented in the emergency department. Patients with self-inflicted injuries who visited 1 of 3 sentinel emergency medical centers from 2007 through 2009 were included in the study. The characteristics, methods, and reasons for suicide attempts were evaluated. Moreover, predictors of severe outcomes were evaluated. A total of 2,996 patients with self-inflicted injuries visited the three centers during a period of 3 yr. The male-to-female suicide ratio was 1:1.38 (P < 0.001). The mean age was 41 yr. Poisoning was the most common method of self-inflicted injury (68.7%) among all age groups. Medication was the primary means of injury in the < 50 age group, and the use of agricultural chemicals was the primary means in the ≥ 50 age group. The reasons for attempting suicide varied among the age groups. The predictors of severe outcome are male gender, older age, and not having consumed alcohol.

Fulminant and Fatal Multiple Organ Failure in a 12-Year-Old Boy With Mycoplasma pneumoniae Infection

Mycoplasma pneumoniae (Mp) is a unique pathogen that causes not only pulmonary but also extrapulmonary manifestations that must be rapidly diagnosed. A 12-year-old boy, with no relevant medical history, presented with fever, severe epigastric pain, and vomiting. Laboratory findings showed fulminant and cholestatic hepatitis, hemolytic anemia, thrombocytopenia, acute kidney injury, disseminated intravascular coagulopathy, acute myocardial infarction, and rhabdomyolysis. His clinical condition rapidly deteriorated during intubation and continuous renal replacement therapy. Despite intensive treatment, he did not recover. We report a case of fulminant and fatal multiple organ failure in a previously healthy boy with Mp infection, describing the possible pathomechanisms of multiple organ failure involved in the disease.

Cyclosporin A therapy for Henoch-Schönlein nephritis with nephrotic-range proteinuria

To evaluate the therapeutic role of cyclosporin A (CyA) for the treatment of Henoch-Schönlein nephritis (HSN), 29 patients (18 boys, 11 girls) with nephrotic-range proteinuria were analyzed retrospectively. Mean age was 8.6 years (range 2.0-15.5 years) at diagnosis of Henoch-Schönlein purpura (HSP). All patients had developed the nephrotic-range proteinuria at a mean interval of 4.4 months (range 0-50.7 months) after the diagnosis of HSP. Mean duration of CyA treatment was 12.3 months (range 2.6-55.0 months). Mean follow-up times were 3.7 years (range 1.2-12.9 years) from the beginning of the CyA treatment. Steroids were tapered off and stopped gradually after initiation of CyA. All patients responded to the CyA treatment within a mean of 1.8 months (range 1 week to 3.5 months). Twenty-three patients achieved stable remission with mean follow-up duration of 3.2 years and 6 patients seemed to become CyA-dependent, since they developed proteinuria when the treatment was stopped. Renal function was preserved in all patients but one who developed end-stage renal disease after poor compliance with CyA. We concluded that CyA treatment for HSN showing nephrotic-range proteinuria is very effective and a safe method, although some patients become CyA-dependent.

Partial tetrasomy of chromosome 22q11.1 resulting from a supernumerary isodicentric marker chromosome in a boy with cat-eye syndrome

The 22q11 region has been implicated in chromosomal rearrangements that result in altered gene dosage, leading to three different congenital malformation syndromes: DiGeorge syndrome, cat-eye syndrome (CES), and der(22) syndrome. Although DiGeorge syndrome is a common genomic disorder on 22q11, CES is quite rare, and there has been no report of Korean CES cases with molecular cytogenetic confirmation. In this study, we present the phenotypic and genetic characteristics of a 3-month-old boy with CES. Clinical findings included micropthalmia, multiple colobomata, and renal and genital anomalies. Cytogenetic analyses showed the presence of a supernumerary marker chromosome, which was identified as a bisatellited and isodicentric chromosome derived from an acrocentric chromosome. The results of array comparative genomic hybridization and fluorescence in situ hybridization studies confirmed the karyotype as 47,XY,+mar.ish idic(22)(q11.1) (D22S43+).arr 22q11.1(15,500,000-15,900,000)x4, resulting in a partial tetrasomy of 22q11.1. To the best of our knowledge, this is the first report in Korea of CES confirmed by cytogenetic and molecular cytogenetic analyses.

Acute peritoneal dialysis in very low birth weight neonates using a vascular catheter

We report on our experience with acute peritoneal dialysis (APD) in 16 very low birth weight neonates ranging from 24.6 to 30.2 weeks' gestation with a birth weight ranging from 630 g to 1,430 g using a 14-gauge Arrow vascular catheter for APD access. The underlying causes of acute renal failure were: sepsis (7), necrotizing enterocolitis (4), patent ductus arteriosus (3), hydrops fetalis (1), intracranial hemorrhage (3), pulmonary hemorrhage (2), pneumonia (1), and perinatal asphyxia (1). Among 12 patients, the APD was successful for the control of hyperkalemia, fluid overload, and metabolic acidosis. The peritoneal permeability and transport were at their maximum at a short dwell time with rapid exchanges. Complications associated with the APD were: peritonitis (2), leakage (2), hemoperitoneum (1), and hernia (1). During the dialysis, four patients died; there were three episodes of catheter-related complications in these patients. At 60 days after the withdrawal of the APD, 10 patients were alive, and had full recovery of their renal function. Therefore, APD in premature neonates with a 14-gauge Arrow vascular catheter was safe and effective. This procedure helped manage the hemodynamic and metabolic imbalance of acute renal failure and was associated with few complications.

Prevalence and associated factors of overactive bladder in Korean children 5-13 years old: a nationwide multicenter study

OBJECTIVES

To estimate the prevalence of overactive bladder (OAB) in Korean children, 5-13 years of age, and to assess the associated factors for OAB.

METHODS

A randomly selected cross-section study was conducted in 26 kindergartens and 27 elementary schools nationwide in Korea. A total of 19 240 children were included; a parent was asked to complete the questionnaires, which included items about OAB and voiding and defecating habits. OAB was defined as urgency with or without urge incontinence, usually with increased daytime frequency and nocturia (International Children's Continence Society, 2006). Its prevalence and associated factors were also investigated.

RESULTS

The response rate for the questionnaires was 85.84%. The overall prevalence of OAB was 16.59%. The prevalence of OAB decreased with age from 22.99% to 12.16% (P = .0001). The overall incidence of wet and dry OAB was 26.97% and 73.03%, respectively. Compared with normal children, those with OAB had a greater prevalence of nocturnal enuresis, constipation, fecal incontinence, urinary tract infection, delayed bladder control, and poor toilet facilities (P < .05). The incidence of increased daytime frequency and urge incontinence was 3.69% and 2.31% (P = .009) and 26.97% and 14.78% (P = .0001) in OAB and non-OAB children, respectively. The corresponding prevalence decreased with age from 5.04% to 3.06% and from 45.74% to 18.50% in OAB children (P = .0001).

CONCLUSIONS

The overall prevalence of OAB in Korean children, 5-13 years of age, was 16.59% and decreased with age. Nocturnal enuresis, constipation, fecal incontinence, history of urinary tract infection, delayed bladder control, and poor toilet facilities might be factors associated with the development of OAB.

Tissue-engineered Cartilage Using Fibrin/Hyaluronan Composite Gel and Its In Vivo Implantation

The importance of scaffold biomaterials has been emphasized for in vitro culture of tissue-engineered cartilage in a three-dimensional (3D) environment. In this study, we examined the feasibility of fibrin glue, mixed with hyaluronic acid (HA) as a composite scaffold. Fibrin glue has been a useful cell delivery matrix for cartilage tissue engineering and HA is a key component of normal articular cartilage. Our hypothesis is that compared to fibrin itself, a fibrin/HA composite can have significantly enhanced properties, due mainly to the added benefits of HA in the matrix. Pieces of cartilage were isolated from rabbit knees and the chondrocytes were harvested through enzymatic digestion. Both fibrin and fibrin/HA composite were prepared and subsequently implanted in nude mice (n = 9, each group) for 1, 2, and 4 weeks, respectively. The retrieved specimens were then analyzed and the results were compared. Cartilage-like tissue formation was detected earlier with fibrin/HA specimens. They produced significantly higher amounts of the extracellular matrix (ECM) molecules, GAG, and collagen at each time point than those in fibrin. Interestingly, the fibrin/HA composite was also competent in maintaining its initial size. Histology--Safranin O/fast green and Alcian blue--of the retrieved specimens found more intense, uniform staining in the fibrin/HA composites. Analysis of the gene expression of the ECM molecules also confirmed the benefits of the composite with added HA in the maintenance of phenotypic stability. The present study suggests that fibrin/HA composite may serve as a dependable cell delivery vehicle as well as a structural basis for tissue-engineered cartilage.

Diphyllobothrium latum infection after eating domestic salmon flesh

Diphyllobothrium latum infection in human is not common in Korea and only thirty seven cases have been reported since 1921. We report two cases of fish tapeworm infection after ingestion of raw cherry salmon (Oncorhynchus masou) caught in the domestic river. Among four family members who ate together raw salmon flesh six months ago, just two, mother and daughter, were infected. It is our expectation that the salmon associated tapeworm infections would be enlisted as one of the major parasitic problems with the growing consumption of salmon in Korea.

Thrombin receptor signaling to cytoskeleton requires Hsp90

Thrombin is a serine protease that evokes various cellular responses involved in injury and repair of the nervous system through the activation of protease-activated receptor-1 (PAR-1). Signals that modulate cell morphology precede most PAR-1 effects, but the initial signal transduction molecules are not known. Using the yeast two-hybrid system, we identified Hsp90, a chaperone with known signaling properties, as a binding partner of PAR-1. The interaction was confirmed by glutathione S-transferase pull-down, overlay, and co-immunoprecipitation assays. Morphological assays in mouse astrocytes were carried out to evaluate the importance of Hsp90 during cytoskeletal signaling. Reducing Hsp90 levels by antisense treatment or disruption of the Hsp90.PAR-1 complex by the Hsp90-specific drug geldanamycin attenuated thrombin-mediated astrocyte shape changes. Furthermore, overexpression of the PAR-1 cytoplasmic tail abrogated thrombin-induced cytoskeletal changes in neuronal cells. Treatment with geldanamycin specifically inhibited activation of RhoA without affecting thrombin-mediated intracellular calcium release, revealing the regulation of a distinct signaling pathway by Hsp90. Taken together, these studies demonstrate that Hsp90 may be essential for PAR-1-mediated signaling to the cytoskeleton.

Structural and functional analysis of a bipolar replication terminus. Implications for the origin of polarity of fork arrest

We have delineated the amino acid to nucleotide contacts made by two interacting dimers of the replication terminator protein (RTP) of Bacillus subtilis with a novel naturally occurring bipolar replication terminus by converting RTP to a site-directed chemical nuclease and mapping its cleavage sites on the terminus. The data show a relatively symmetrical arrangement of the amino acid to base contacts, and a comparison of the bipolar contacts with that of a normal unipolar terminus suggests that the DNA-protein contacts play an important determinative role in generating polarity from structurally symmetrical RTP dimers. The amino acid to nucleotide contacts provided distance constraints that enabled us to build a three-dimensional model of the protein-DNA complex. The model is consistent with features of the bipolar Ter.RTP complex derived from mutational and cross-linking data. The bipolar terminus arrested Escherichia coli DNA replication and DnaB helicase and T7 RNA polymerase in vitro in both orientations. RTP arrested the unwinding of duplex DNA on the bipolar Ter DNA substrate regardless of the length of the duplex DNA. The latter result suggested further that the terminus arrested authentic DNA unwinding by the helicase rather than just translocation of helicase on DNA.

Effect of grapefruit juice on cyclosporin A pharmacokinetics in pediatric renal transplant patients

Cyclosporin A (CsA) is an important immunosuppressant that is prone to numerous drug interactions. Grapefruit juice has been investigated, as a possible adjunct to CsA dosing in adult renal transplant recipients, to decrease CsA metabolism and reduce dosages. This study investigated this combination in pediatric renal transplant patients. Six stable pediatric renal transplant patients were entered into an open-label, four-period cross-over study in which patients were given their current CsA dose as either an oral solution (CsA-Sol) or a microemulsion (CsA-ME). In addition, drugs were administered concurrently with water or grapefruit juice. Steady-state pharmacokinetic profiles were taken during each of the four periods. Following the concurrent administration of grapefruit juice, CsA whole-blood 12-h trough levels were significantly increased during CsA-Sol dosing. Furthermore, the CsA elimination rate constant was significantly reduced during the same period. After CsA-ME dosing, no differences in CsA pharmacokinetics were found between concurrent water or grapefruit ingestion. Grapefruit juice co-administration reduced the production of CsA metabolites, AM1 and AM9, during CsA-Sol dosing. No changes in CsA metabolite production were found when patients were given CsA-ME with grapefruit juice as compared with water. Hence, alterations in CsA absorption and elimination occur with concurrent grapefruit juice ingestion when stable pediatric renal transplant patients are taking the oral CsA solution, but not the microemulsion formulation. These changes may be mediated by alterations in intestinal or hepatic metabolism, or drug absorption. The effect of grapefruit juice on CsA absorption is not readily predictable in these patients.

Creatine kinase, an ATP-generating enzyme, is required for thrombin receptor signaling to the cytoskeleton

Thrombin orchestrates cellular events after injury to the vascular system and extravasation of blood into surrounding tissues. The pathophysiological response to thrombin is mediated by protease-activated receptor-1 (PAR-1), a seven-transmembrane G protein-coupled receptor expressed in the nervous system that is identical to the thrombin receptor in platelets, fibroblasts, and endothelial cells. Once activated by thrombin, PAR-1 induces rapid and dramatic changes in cell morphology, notably the retraction of growth cones, axons, and dendrites in neurons and processes in astrocytes. The signal is conveyed by a series of localized ATP-dependent reactions directed to the actin cytoskeleton. How cells meet the dynamic and localized energy demands during signal transmission is unknown. Using the yeast two-hybrid system, we identified an interaction between PAR-1 cytoplasmic tail and the brain isoform of creatine kinase, a key ATP-generating enzyme that regulates ATP within subcellular compartments. The interaction was confirmed in vitro and in vivo. Reducing creatine kinase levels or its ATP-generating potential inhibited PAR-1-mediated cellular shape changes as well as a PAR-1 signaling pathway involving the activation of RhoA, a small G protein that relays signals to the cytoskeleton. Thrombin-stimulated intracellular calcium release was not affected. Our results suggest that creatine kinase is bound to PAR-1 where it may be poised to provide bursts of site-specific high-energy phosphate necessary for efficient receptor signal transduction during cytoskeletal reorganization.

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 generation of oxidative stress in brain by MPTP: in vitro and in vivo studies in mice

The role of oxidative stress in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-mediated neurotoxicity is as yet unclear and the evidence for generation of oxygen free radicals as a primary event in the neurotoxicity is yet to be demonstrated. The present study was undertaken to ascertain the potential role of oxidative damage, and the protective role, if any, of the antioxidant, glutathione (GSH), in MPTP-induced neurotoxicity. Exposure of sagittal slices of mouse brain to MPTP resulted in significant increases of reactive oxygen species (ROS) and malondialdehyde (MDA, the product of lipid peroxidation) and decreases in GSH content. Pretreatment of mouse brain slices, in vitro, with GSH or GSH isopropyl ester attenuated MPTP toxicity as assessed by the tissue activity of the mitochondrial enzyme, NADH-dehydrogenase (NADH-DH), and by leakage of the cytosolic enzyme, lactate dehydrogenase (LDH), from the slice into the medium. In vivo administration of MPTP (30 mg/kg body weight, s.c.), to mice resulted in significant lowering of GSH in the striatum and midbrain, 2 h after dosage; ROS levels in the striatum and midbrain increased after 4 and 8 h, respectively. In the striatum significant inhibition of rotenone-sensitive NADH ubiquinone-1 oxido-reductase (Complex 1) was observed transiently 1 h after MPTP administration. The enzyme activity recovered thereafter; significant inhibition of mitochondrial Complex I was observed in the striatum only 18 h after MPTP dose. In the midbrain, mitochondrial Complex I was inhibited only 18 h after MPTP dose; no change was observed at the early time points examined. Thus, the depletion of GSH and increased ROS formation preceded the inhibition of the mitochondrial enzyme in the midbrain. Evidence presented herein from both in vitro and in vivo studies support that MPTP exposure generates ROS resulting in oxidative stress.

Helicase-contrahelicase interaction and the mechanism of termination of DNA replication

Termination of DNA replication at a sequence-specific replication terminus is potentiated by the binding of the replication terminator protein (RTP) to the terminus sequence, causing polar arrest of the replicative helicase (contrahelicase activity). Two alternative models have been proposed to explain the mechanism of replication fork arrest. In the first model, the RTP-terminus DNA interaction simply imposes a polar barrier to helicase movement without involving any specific interaction between the helicase and the terminator proteins. The second model proposes that there is a specific interaction between the two proteins, and that the DNA-protein interaction both restricts the fork arrest to the replication terminus and determines the polarity of the process. The evidence presented in this paper strongly supports the second model.

Structure of the replication terminus-terminator protein complex as probed by affinity cleavage

The replication terminator protein (RTP) of Bacillus subtilis is a homodimer that binds to each replication terminus and impedes replication fork movement in only one orientation with respect to the replication origin. The three-dimensional structure of the RTP-DNA complex needs to be determined to understand how structurally symmetrical dimers of RTP generate functional asymmetry. The functional unit of each replication terminus of Bacillus subtilis consists of four turns of DNA complexed with two interacting dimers of RTP. Although the crystal structure of the RTP apoprotein dimer has been determined at 2.6-A resolution, the functional unit of the terminus is probably too large and too flexible to lend itself to cocrystallization. We have therefore used an alternative strategy to delineate the three dimensional structure of the RTP-DNA complex by converting the protein into a site-directed chemical nuclease. From the pattern of base-specific cleavage of the terminus DNA by the chemical nuclease, we have mapped the amino acid to base contacts. Using these contacts as distance constraints, with the crystal structure of RTP, we have constructed a model of the DNA-protein complex. The biological implications of the model have been discussed.

The structure and function of the replication terminator protein of Bacillus subtilis: identification of the 'winged helix' DNA-binding domain

The replication terminator protein (RTP) of Bacillus subtilis impedes replication fork movement in a polar mode upon binding as two interacting dimers to each of the replication termini. The mode of interaction of RTP with the terminus DNA is of considerable mechanistic significance because the DNA-protein complex not only localizes the helicase-blocking activity to the terminus, but also generates functional asymmetry from structurally symmetric protein dimers. The functional asymmetry is manifested in the polar impedance of replication fork movement. Although the crystal structure of the apoprotein has been solved, hitherto there was no direct evidence as to which parts of RTP were in contact with the replication terminus. Here we have used a variety of approaches, including saturation mutagenesis, genetic selection for DNA-binding mutants, photo cross-linking, biochemical and functional characterizations of the mutant proteins, and X-ray crystallography, to identify the regions of RTP that are either in direct contact with or are located within 11 angstroms of the replication terminus. The data show that the unstructured N-terminal arm, the alpha3 helix and the beta2 strand are involved in DNA binding. The mapping of amino acids of RTP in contact with DNA, confirms a 'winged helix' DNA-binding motif.

The dimer-dimer interaction surface of the replication terminator protein of Bacillus subtilis and termination of DNA replication

The replication terminator protein (RTP) of Bacillus subtilis causes polar fork arrest at replication termini by sequence-specific interaction of two dimeric proteins with the terminus sequence. The crystal structure of the RTP protein has been solved, and the structure has already provide valuable clues regarding the structural basis of its function. However, it provides little information as to the surface of the protein involved in dimer-dimer interaction. Using site-directed mutagenesis, we have identified three sites on the protein that appear to mediate the dimer-dimer interaction. Crystallographic analysis of one of the mutant proteins (Y88F) showed that its structure is unaltered when compared to the wild-type protein. The locations of the three sites suggested a model for the dimer-dimer interaction that involves an association between two beta-ribbon motifs. This model is supported by a fourth mutation that was predicted to disrupt the interaction and was shown to do so. Biochemical analyses of these mutants provide compelling evidence that cooperative protein-protein interaction between two dimers of RTP is essential to impose polar blocks to the elongation of both DNA and RNA chains.

Head louse infestation in vagrants and children admitted to public welfare facilities, Republic of Korea

From December 1992 to February 1993, all vagrants and children admitted to public welfare facilities supported by the Government of Republic of Korea were examined for the presence of nit, nymph or adult of head louse. Of 36,055 persons examined, the number of positive was 7,393 (20.5%). Intensive control measures are needed to control this ectoparasitic infestation.

Protection and potentiation of 1-methyl-4-phenylpyridinium-induced toxicity by cytochrome P450 inhibitors and inducer may be due to the altered uptake of the toxin

Earlier studies from our laboratory have demonstrated that 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) toxicity could be modulated by inhibitors and inducer of cytochrome P450 (P450) in an in vitro model consisting of sagittal slices of mouse brain. To understand the molecular mechanisms underlying the role of P450 on MPTP toxicity, it was undertaken to study the effect of the modulators of P450 on the toxicity of the metabolite of MPTP, namely, 1-methyl-4-phenylpyridinium ion (MPP+). Incubation of mouse brain slices with various concentrations of MPP+ (1-100 microM) resulted in dose-dependent inhibition of mitochondrial enzyme NADH-dehydrogenase (NADH-DH) and leakage of the cytosolic enzyme lactate dehydrogenase from the slice into the medium. MPP(+)-induced toxicity was abolished by pretreatment of the slices with inhibitors of monoamine oxidase (MAO; pargyline and deprenyl) or inhibitors of P450 (piperonyl butoxide or SKF-525A) or dopamine uptake blocker (GBR-12909), as measured by the activity of NADH-DH in slices and leakage of lactate dehydrogenase from the slice into the medium. Slices prepared from mice pretreated with phenobarbital (an inducer of P450) potentiated the toxic effects of MPP+. Pretreatment of slices with MAO-inhibitor, P450 inhibitors, or dopamine uptake blocker attenuated the uptake of MPP+ into the slices. In contrast, MPP+ uptake was significantly increased in slices prepared from phenobarbital-pretreated mice. Thus, both MAO and P450 inhibitors abolish the toxicity of MPP+ in the sagittal slices of mouse brain by altering the uptake of the toxin into the slices.

Infestation rate of lice in patients in a mental hospital, Seoul, Korea

We examined the infestation rate of head and/or body lice in patients in a mental hospital, Seoul, Korea on June 27-28, 1988. Of 438 women, 146 (33.3%) were positive with nits or worms of louse. Of 143 men, 22 (15.4%) were positive with those of louse. Regular control programs were necessary to this hospital.

L-BOAA induces selective inhibition of brain mitochondrial enzyme, NADH-dehydrogenase

Lathyrism, a human neurological disorder has been linked to the excessive consumption of a plant toxin, beta-oxalylamino-L-alanine (L-BOAA) present in Lathyrus sativus. The present study was carried out to elucidate the biochemical mechanisms underlying L-BOAA-induced toxic insult. Incubation of sagittal slices of mouse brain with L-BOAA resulted in dose and time-dependent inhibition of mitochondrial NADH-dehydrogenase (NADH-DH). Significant inhibition of NADH-DH was seen following incubation of brain slices with very low concentration of L-BOAA (0.1 pM). L-BOAA also induced lactate dehydrogenase (LDH) leakage from the slice into the medium in dose-dependent manner. The inhibition of NADH-DH preceded LDH leakage from the slices into the medium. L-BOAA had no effect on other mitochondrial enzymes, namely, isocitrate dehydrogenase or cytochrome c oxidase. Incubation of isolated mouse brain mitochondria with L-BOAA also resulted in inhibition of NADH-DH. L-BOAA-induced inhibition of NADH-DH was prevented by non-N-methyl-D-aspartate (non-NMDA) glutamate receptor antagonists in general and alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptor antagonist (NBQX) in particular. Other glutamate agonists examined namely, N-methyl-D-aspartate, beta-N-methylamino-L-alanine (L-BMAA), L-glutamic acid, N-acetylaspartylglutamate (NAAG), quisqualic acid, kainic acid or AMPA did not have any effect on NADH-DH activity in slices although they induced LDH leakage from the slice into the medium. Incubation of brain slices with L-BOAA did not induce lipid peroxidation or changes in glutathione levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Billion-fold difference in the toxic potencies of two excitatory plant amino acids, L-BOAA and L-BMAA: biochemical and morphological studies using mouse brain slices

Plant amino acids beta-N-oxalylamino-L-alanine (L-BOAA, present in Lathyrus sativus) and beta-N-methylamino-L-alanine (L-BMAA, present in Cycas circinalis) have been implicated in the pathogenesis of human neurological disorders lathyrism and amyotrophic lateral sclerosis-Parkinson's dementia complex of Guam (ALS-PD), respectively. In view of the conflicting reports that have emerged on the role of L-BMAA in ALS-PD, we reinvestigated the comparative toxicity of L-BMAA and L-BOAA. We report here the potent toxicity of L-BOAA as examined in an in vitro model consisting of sagittal slices of mouse brain. Incubation of sagittal slices of mouse brain with L-BOAA (1 pM) resulted in significant leakage of lactate dehydrogenase (LDH) and potassium from the slices into the medium. Under similar conditions, L-BMAA-induced LDH leakage from the slices into the medium was observed only at very high concentration of the toxin, namely 1 mM. N-Methyl-D-aspartate (NMDA) receptor antagonists ameliorated the toxic effects of L-BMAA, while non-NMDA receptor antagonists (quinoxalinediones) protected against the toxicity of L-BOAA. Incubation of slices with L-BOAA for 1 h resulted in extensive vacuolation and degeneration of neurons in the thalamus and brain stem, and to a lesser extent in the hippocampus and cerebellar nuclei. The large sized neurons appeared to be affected to a greater extent than the smaller ones. The neurons in other areas of the brain also revealed variable degree of degeneration with swelling of axons and dendrites.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence of head louse infestation in primary school children in Kangwon-do, Korea

We tried to reveal the prevalence rates of the head louse infestation in school children in Kangwon-do, Korea in December 1990. A total of 912 children in four primary schools was examined. The positive rate for adults and/or nits of Pediculus humanus capitis was 37.2%. One school was followed-up without specific intervention. There was no significant change of the prevalence rate 6 months after the first examination from 66.0% to 57.3%. We could see the persistent infestation rate if there was no intervention. We are emphasizing the significance of worm positive rate because it represents the potentiality of active transmission.

Quisqualic acid-induced neurotoxicity is protected by NMDA and non-NMDA receptor antagonists

Quisqualic acid-mediated excitotoxicity has been attributed essentially to the activation of non-N-methyl-D-aspartate (non-NMDA) receptors. In the present study we demonstrate the possible involvement of both NMDA and non-NMDA receptors in quisqualic acid-induced toxicity in mouse brain slices, in vitro. Incubation of mouse brain sagittal slices with various concentrations of quisqualic acid resulted in significant increase in the leakage of lactate dehydrogenase and potassium from the slices into the medium. Prior incubation of mouse brain slices with NMDA (MK-801 or AP7) or non-NMDA receptor antagonists (GDEE or quinoxalinediones) protected against quisqualic acid-mediated toxicity. Slices prepared from animals pretreated in vivo with MK-801 (5 mg/kg b.wt.) were also resistant to the toxic effects of quisqualic acid, indicating the possible involvement of NMDA receptors in quisqualic acid toxicity.

[Head louse infestation among girls in an orphanage and women in a mental hospital and mass-delousing with bioallethrin (PARA aerosol)]

After evaluation of presence of nits and/or lice, PARA aerosol(bioallethrin with piperonyl butoxide) was applied to 97 women and 43 girls, regardless of the results of their infestation, living at 2 separate institutions. Twelve days after the first treatment the second treatment was carried out and the presence of head lice was examined for the evaluation of treatment effect. Among total 140 subjects, 98(70.0%) were nit positive and 85(60.7%) were louse positive. The infestation rates of girls by nit(86.0%) and louse(86.0%) were higher than those of women, nit 62.9% and louse 49.5% (p less than 0.01). Also the detection rate of lice among nit positive subjects was higher in girls(100%) than in women(78.7%). On the second evaluation 12 days after treatment, 36(97.3%) out of 37 girls and 46(95.8%) out of 48 women were found louse-free. There was no difference in the treatment efficacy between the women and girls.

Protection and potentiation of MPTP-induced toxicity by cytochrome P-450 inhibitors and inducer: in vitro studies with brain slices

Exposure to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) causes loss of dopaminergic neurons in humans, primates and mice. Exposure of sagittal slices of mouse brain to MPTP (100 pM) caused inhibition of mitochondrial NADH-dehydrogenase activity. Leakage of lactate dehydrogenase from the slice into the medium was observed following incubation of slices with 1 nM MPTP. Neurotoxicity induced by MPTP was prevented by prior exposure of the slices to the dopamine uptake inhibitor GBR 12935. Deprenyl and pargyline (inhibitors of monoamine oxidase), also protected the slices from MPTP-induced toxicity. However, both pargyline and deprenyl also inhibited cytochrome P-450 mediated aminopyrine N-demethylase activity in brain slices. Pargyline, when administered in vivo to mice, decreased brain cytochrome P-450 levels significantly. Other cytochrome P-450 inhibitors, namely, piperonyl butoxide and SKF 525A were found to offer protection against MPTP induced neurotoxicity in slices without affecting monoamine oxidase activity. MPTP toxicity was potentiated significantly in brain slices prepared from mice pretreated with phenobarbital, an inducer of cytochrome P-450. The present study suggests the possible involvement of cytochrome P-450 in MPTP-induced neurotoxicity, in vitro, in brain slices.

Toxicity of N-acetylaspartylglutamate and its protection by NMDA and non-NMDA receptor antagonists

N-Acetylaspartylglutamate (NAAG) is a dipeptide, and has been demonstrated to be a putative neurotransmitter in the brain. We hereby report the toxicity of NAAG in sagittal slices of mouse brain, in vitro, which is prevented by both N-methyl-D-aspartate (NMDA) and non-NMDA receptor antagonists. Incubation of mouse brain slices with NAAG resulted in dose-dependent leakage of lactate dehydrogenase (LDH) and potassium from the slices into the medium. Significant leakage of LDH was observed when the slices were incubated with 0.1 pM NAAG. Significant leakage of LDH from the slice was observed only when a very high concentration of L-glutamic acid (10 microM) was added to the incubatio medium. Prior incubation with NMDA (MK-801) or non-NMDA (glutamate diethyl ester, (GDEE] receptor antagonists protected the slices against NAAG-mediated neurotoxicity, indicating the possible involvement of both of these classes of receptors in the toxic action of NAAG.

A simple and inexpensive slicer for preparation of brain slices

A simple and inexpensive slicer has been developed for the preparation of slices of mouse or rat brain. The instrument consists of razor blades, separated by an 0.5 mm thick polyethylene sheet (1 x 1 cm), mounted on metal screws through a hole in the center of the polyethylene sheet. Using this slicer, 6-8 uniform slices of 500 microns thickness were obtained from mouse or rat brain. These brain slices were incubated in a medium consisting of artificial cerebrospinal fluid for 1 h at 37 degrees C under an oxygen atmosphere and the activities of various subcellular marker enzymes were assayed. The slice weights and the activities of the enzymes did not vary significantly in different batches of slices. Morphological evaluation of the slices revealed well-preserved neurons. Histochemical staining for mitochondrial enzymes revealed intense staining of neuronal cells and lighter staining of the white matter in all the regions examined. These slices could serve as a useful in vitro model for studying brain function and the effect of various toxicants on the brain.

[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.

[Head louse infestation among school children in Sanbuk-myon, Mungyong-gun, Kyongsangbuk-do (1985)]

In order to know the prevalence of head louse among the school children in rural area, we visited 3 primary schools and a kindergarten in Sanbuk-myon, Mungyong-gun, Kyongsangbuk-do in July 1985, and examined the children to identify the adult worms of head louse and/or its nits on the hair. The overall infestation rate was 91.9% among 420 children examined, and there was a difference between schools (P< 0.05). the school girls' rate, 96.1% was higher than that of bods' 88.9%(P< 0.05). By grade, the rate of infant school was 88.5% and 1st to 6th grade were 100, 100, 95.8, 90.4 89.7, 80.0% respectively. Above result indicates that the head louse is an important health problem in this community. Therefore, the chemotherapy and the effort to improve the hygiene are necessary in this community by physicians, teachers and health administrators.