The Japanese Society for Apheresis clinical practice guideline for therapeutic apheresis

Most of the diseases for which apheresis therapy is indicated are intractable and rare, and each patient has a different background and treatment course prior to apheresis therapy initiation. Therefore, it is difficult to conduct large-scale randomized controlled trials to secure high-quality evidence. Under such circumstances, the American Society for Apheresis (ASFA) issued its guidelines in 2007, which were repeatedly revised until the latest edition in 2019. The ASFA guidelines are comprehensive. However, in the United States, a centrifugal separation method is mainly used for apheresis, whereas the mainstream procedure in Japan is the membrane separation method. The target diseases and their backgrounds are different from those in Japan. Due to these differences, the direct adoption of the ASFA guidelines in Japanese practice creates various problems. One of the features of apheresis in Japan is the development of treatment methods using hollow-fiber devices such as double filtration plasmapheresis (DFPP) and selective plasma exchange and adsorption-type devices such as polymyxin B-immobilized endotoxin adsorption columns. Specialists in emergency medicine, hematology, collagen diseases/rheumatology, respiratory medicine, cardiovascular medicine, gastroenterology, neurology, nephrology, and dermatology who are familiar with apheresis therapy gathered for this guideline, which covers 86 diseases. In addition, since apheresis therapy involves not only physicians but also clinical engineers, nurses, dieticians, and many other medical professionals, this guideline was prepared in the form of a worksheet so that it can be easily understood at the bedside. Moreover, to the clinical purposes, this guideline is designed to summarize apheresis therapy in Japan and to disseminate and further develop Japanese apheresis technology to the world. As diagnostic and therapeutic techniques are constantly advancing, the guidelines need to be revised every few years. In order to ensure the high quality of apheresis therapy in Japan, both the Japanese Society for Apheresis Registry and the guidelines will be inseparable.

COVID-19 Transmission at Schools in Japan

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), remains a global public health concern in 2021. However, the risk of attending schools during the pandemic remains unevaluated. This study estimated the secondary transmission rate at schools using the results of a real-time reverse transcription-polymerase chain reaction (RT-PCR) screening test performed between July 2020 and April 2021, before starting the nationwide mass vaccination. A total of 1,924 students (20 RT-PCR-positive; 1.0%) from 52 schools or preschools were evaluated, together with 1,379 non-adults (95 RT-PCR-positive; 6.9%) exposed to SARS-CoV-2 in non-school environments. Assuming that the infectious index cases were asymptomatic and the transmission at schools followed a Bernoulli process, we estimated the probability of transmission after each contact at school as approximately 0.005 (0.5% per contact) with the current infection prevention measures at schools in Japan (i.e., hand hygiene, physical distancing, wearing masks, and effective ventilation). Furthermore, assuming that all children are capable of carrying the infection, then contact between an index case and 20-30 students per day at schools would yield the expected value for secondary cases of ≥ 1.0, during the 10 days of the infectious period. In conclusion, with the current infection prevention measures at schools in Japan, secondary transmission at schools would occur in approximately every 200 contacts. When considering this rate, compliance with the current infection prevention measures at schools and early detection and quarantine of the index cases would be effective in preventing the spread of COVID-19 at schools.

Clear Evidence of LAMA5 Gene Biallelic Truncating Variants Causing Infantile Nephrotic Syndrome

Background

Pathogenic variants in single genes encoding podocyte-associated proteins have been implicated in about 30% of steroid-resistant nephrotic syndrome (SRNS) patients in children. However, LAMA5 gene biallelic variants have been identified in only seven patients so far, and most are missense variants of unknown significance. Furthermore, no functional analysis had been conducted for all but one of these variants. Here, we report three patients with LAMA5 gene biallelic truncating variants manifesting infantile nephrotic syndrome, and one patient with SRNS with biallelic LAMA5 missense variants.

Methods

We conducted comprehensive gene screening of Japanese patients with severe proteinuria. With the use of targeted next-generation sequencing, 62 podocyte-related genes were screened in 407 unrelated patients with proteinuria. For the newly discovered LAMA5 variants, we conducted in vitro heterotrimer formation assays.

Results

Biallelic truncating variants in the LAMA5 gene (NM_005560) were detected in three patients from two families. All patients presented with proteinuria within 6 months of age. Patients 1 and 2 were siblings possessing a nonsense variant (c.9232C>T, p.[Arg3078*]) and a splice site variant (c.1282 + 1G>A) that led to exon 9 skipping and a frameshift. Patient 3 had a remarkable irregular contour of the glomerular basement membrane. She was subsequently found to have a nonsense variant (c.8185C>T, p.[Arg2720*]) and the same splice site variant in patients 1 and 2. By in vitro heterotrimer formation assays, both truncating variants produced smaller laminin α5 proteins that nevertheless formed trimers with laminin β1 and γ1 chains. Patient 4 showed SRNS at the age of 8 years, and carried compound heterozygous missense variants (c.1493C>T, p.[Ala498Val] and c.8399G>A, p.[Arg2800His]).

Conclusions

Our patients showed clear evidence of biallelic LAMA5 truncating variants causing infantile nephrotic syndrome. We also discerned the clinical and pathologic characteristics observed in LAMA5-related nephropathy. LAMA5 variant screening should be performed in patients with congenital/infantile nephrotic syndrome.

Impacts of Natural Environmental Factors and Prevalence of Airway Symptoms on the Local Spread of COVID-19: A Time-Series Analysis in Regional COVID-19 Epidemics

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is the world's largest public health concern in 2021. This study evaluated the associations of the prevalence of airway symptoms among the tested individuals and data regarding the natural environmental factors with the weekly number of newly diagnosed COVID-19 patients in Sendai City (N_t). For the derivatives of the screening test results, data from individuals with a contact history who underwent nasopharyngeal swab reverse transcription-polymerase chain reaction (RT-PCR) testing between July 2020 and April 2021 (6,156 participants, including 550 test-positive patients) were used. The value of N_t correlated with the weekly RT-PCR test-positive rate after close contact, prevalence of cough symptoms in test-positive individuals or in test-negative individuals, lower air temperature, lower air humidity, and higher wind speed. The weekly test-positive rate correlated with lower air humidity and higher wind speed. In cross-correlation analyses, natural environmental factors correlated with the regional epidemic status on a scale of months, whereas the airway symptoms among non-COVID-19 population affected on a scale of weeks. When applying an autoregression model to the serial data of N_t, large-scale movements of people were suggested to be another factor to influence the local epidemics on a scale of days. In conclusion, the prevalence of cough symptoms in the local population, lower air humidity or higher wind speed, and large-scale movements of people in the locality would jointly influence the local epidemic status of COVID-19.

Deletion in the Cobalamin Synthetase W Domain-Containing Protein 1 Gene Is associated with Congenital Anomalies of the Kidney and Urinary Tract

BACKGROUND

Researchers have identified about 40 genes with mutations that result in the most common cause of CKD in children, congenital anomalies of the kidney and urinary tract (CAKUT), but approximately 85% of patients with CAKUT lack mutations in these genes. The anomalies that comprise CAKUT are clinically heterogenous, and thought to be caused by disturbances at different points in kidney development. However, identification of novel CAKUT-causing genes remains difficult because of their variable expressivity, incomplete penetrance, and heterogeneity.

METHODS

We investigated two generations of a family that included two siblings with CAKUT. Although the parents and another child were healthy, the two affected siblings presented the same manifestations, unilateral renal agenesis and contralateral renal hypoplasia. To search for a novel causative gene of CAKUT, we performed whole-exome and whole-genome sequencing of DNA from the family members. We also generated two lines of genetically modified mice with a gene deletion present only in the affected siblings, and performed immunohistochemical and phenotypic analyses of these mice.

RESULTS

We found that the affected siblings, but not healthy family members, had a homozygous deletion in the Cobalamin Synthetase W Domain-Containing Protein 1 (CBWD1) gene. Whole-genome sequencing uncovered genomic breakpoints, which involved exon 1 of CBWD1, harboring the initiating codon. Immunohistochemical analysis revealed high expression of Cbwd1 in the nuclei of the ureteric bud cells in the developing kidneys. Cbwd1-deficient mice showed CAKUT phenotypes, including hydronephrosis, hydroureters, and duplicated ureters.

CONCLUSIONS

The identification of a deletion in CBWD1 gene in two siblings with CAKUT implies a role for CBWD1 in the etiology of some cases of CAKUT.

New-onset diabetes after renal transplantation in a patient with a novel HNF1B mutation

CAKUT are the most frequent causes of ESRD in children. Mutations in the gene encoding HNF1B, a transcription factor involved in organ development and maintenance, cause a multisystem disorder that includes CAKUT, diabetes, and liver dysfunction. Here, we describe the case of a patient with renal hypodysplasia who developed NODAT presenting with liver dysfunction. The NODAT was initially thought to be steroid and FK related. However, based on the patient's clinical features, including renal hypodysplasia and recurrent elevations of transaminase, screening for an HNF1B mutation was performed. Direct sequencing identified a novel splicing mutation of HNF1B, designated c.344 + 2T>C. Because CAKUT is the leading cause of ESRD in children and HNF1B mutations can cause both renal hypodysplasia and diabetes, HNF1B mutations may account for a portion of the cases of NODAT in pediatric patients who have undergone kidney transplantation. NODAT is a serious and major complication of solid organ transplantation and is associated with reduced graft survival. Therefore, for the appropriate management of kidney transplantation, screening for HNF1B mutations should be considered in pediatric patients with transplants caused by CAKUT who develop NODAT and show extra-renal symptoms.

Analysis of the genes responsible for steroid-resistant nephrotic syndrome and/or focal segmental glomerulosclerosis in Japanese patients by whole-exome sequencing analysis

Steroid-resistant nephrotic syndrome (SRNS) represents glomerular disease resulting from a number of different etiologies leading to focal segmental glomerulosclerosis (FSGS). Recently, many genes causing SRNS/FSGS have been identified. These genes encode the proteins associated with the formation and/or maintenance of glomerular filtration barrier. Next-generation sequencing is used to analyze large numbers of genes at lower costs. To identify the genetic background of Japanese patients, we studied 26 disease-causing genes using whole-exome sequencing analysis in 24 patients with SRNS and/or FSGS from 22 different Japanese families. We finally found eight causative gene mutations, four recessive and four dominant gene mutations, including three novel mutations, in six patients from five different families, and one novel predisposing mutation in two patients from two different families. Causative gene mutations have only been identified in ~20% of families and further analysis is necessary to identify the unknown disease-causing gene. Identification of the disease-causing gene would support clinical practices, including the diagnosis, understanding of pathogenesis and treatment.

Decreased glomerular filtration as the primary factor of elevated circulating suPAR levels in focal segmental glomerulosclerosis

BACKGROUND

Circulating factor(s) has been thought to be the underlying cause of focal segmental glomerulosclerosis (FSGS), and recent studies foster this idea by demonstrating increased soluble urokinase receptor (suPAR) levels in the serum of FSGS patients.

METHODS

To explore the possible contribution of suPAR in FSGS pathogenesis, we analyzed serum suPAR levels in 17 patients with FSGS and compared them with those in patients with steroid-sensitive nephrotic syndrome, chronic glomerulonephritis, or non-glomerular kidney diseases.

RESULTS

Serum suPAR levels in patients with FSGS were higher than those in patients with steroid-sensitive nephrotic syndrome or chronic glomerulonephritis, but not higher than those in patients with non-glomerular kidney diseases. suPAR levels negatively correlate with estimated glomerular filtration rate and were decreased after renal transplantation in patients with FSGS as well as in those with non-glomerular kidney diseases. Furthermore, 6 FSGS patients with post-transplant recurrence demonstrated that suPAR levels were not high during the recurrence.

CONCLUSIONS

Based on our results, elevated suPAR levels in FSGS patients were attributed mainly to decreased glomerular filtration. These data warrant further analysis for involvement of possible circulating factor(s) in FSGS pathogenesis.

Successful living-related kidney transplantation in a boy with inherited dysfibrinogenemia

In kidney transplantation, it is essential to avoid acute vascular complications, such as hemorrhage and renal vascular thrombosis, which may often lead to allograft loss. Inherited dysfibrinogenemia is a rare coagulation disorder with a wide spectrum of clinical manifestations, such as excessive bleeding and thrombosis. A 12-yr-old boy, previously diagnosed with renal hypodysplasia, was found to have reduced fibrinogen concentrations. Coagulation tests assessing surgical risk during kidney transplantation showed a discrepancy between functional and immunologic fibrinogen concentrations. Gene analysis confirmed inherited dysfibrinogenemia, with a heterozygous mutation in FGA (Aα Arg16His) in the patient and his mother. Based on the molecular and functional properties of the mutation, and a familial phenotype, in which his aunt had experienced a previous bleeding episode, the patient was considered at greater risk of bleeding than of thrombosis. The patient was administered fibrinogen concentrate before surgery, and kidney transplantation was performed with his father as the organ donor. The patient received additional prophylactic infusions of fibrinogen concentrate postoperatively, and his postoperative course was uneventful. Accurate diagnosis of dysfibrinogenemia, including gene analysis, is important for correctly managing patients with this coagulation disorder who are undergoing kidney transplantation.

LMX1B mutation with residual transcriptional activity as a cause of isolated glomerulopathy

BACKGROUND

Nail-patella syndrome (NPS) is a rare autosomal-dominant disorder caused by LMX1B mutation. In patients with the renal lesions typical of NPS without skeletal or nail findings, it is described as nail-patella-like renal disease (NPLRD). However, the pathogenesis of NPLRD is largely unknown.

METHODS

A 6-year-old girl with microscopic haematuria and mild proteinuria was diagnosed with NPLRD because of an aberrantly thickened glomerular basement membrane (GBM) and deposition of Type III collagen in the GBM observed by electron microscopy. Immunohistological analyses of podocyte protein expression were performed on biopsy tissues. Sequence analysis of LMX1B was performed, and the functional consequences of the detected mutation were analysed by luciferase reporter assay.

RESULTS

When analysing molecules that are important for podocyte development, maintenance and maturation, CD2AP expression was found to be altered in the podocytes. A novel LMX1B missense mutation (R246Q) was identified. Functional analyses revealed partial but significant impairment of R246Q transcriptional activity. However, no dominant-negative effect of R246Q was detected, which suggests that NPLRD is caused by LMX1B haploinsufficiency.

CONCLUSIONS

This is the first report on LMX1B mutation identified in a patient with NPLRD. Residual transcriptional activity would account for normality of the nails and patella in this case. Genetic and pathological analyses of additional cases would clarify the role of LMX1B in glomerulopathy without systemic symptoms, which, together with nephropathy in NPS, can be designated as 'LMX1B nephropathy'.

SIRPα interacts with nephrin at the podocyte slit diaphragm

The slit diaphragm (SD) is an intercellular junction between renal glomerular epithelial cells (podocytes) that is essential for permselectivity in glomerular ultrafiltration. The SD components, nephrin and Neph1, assemble a signaling complex in a tyrosine phosphorylation dependent manner, and regulate the unique actin cytoskeleton of podocytes. Mutations in the NPHS1 gene that encodes nephrin cause congenital nephrotic syndrome (CNS), which is characterized by the loss of the SD and massive proteinuria. Recently, we have identified the expression of the transmembrane glycoprotein signal regulatory protein α (SIRPα) at the SD. In the present study, we analyzed the expression of SIRPα in developing kidneys, in kidneys from CNS patients and in proteinuric rat models. The possibility that SIRPα interacts with known SD proteins was also investigated. SIRPα was concentrated at the SD junction during the maturation of intercellular junctions. In the glomeruli of CNS patients carrying mutations in NPHS1, where SD formation is disrupted, the expression of SIRPα as well as Neph1 and nephrin was significantly decreased, indicating that SIRPα is closely associated with the nephrin complex. Indeed, SIRPα formed hetero-oligomers with nephrin in cultured cells and in glomeruli. Furthermore, the cytoplasmic domain of SIRPα was highly phosphorylated in normal glomeruli, and its phosphorylation was dramatically decreased upon podocyte injury in vivo. Thus, SIRPα interacts with nephrin at the SD, and its phosphorylation is dynamically regulated in proteinuric states. Our data provide new molecular insights into the phosphorylation events triggered by podocyte injury.

Generation and analyses of R8L barttin knockin mouse

Barttin, a gene product of BSND, is one of four genes responsible for Bartter syndrome. Coexpression of barttin with ClC-K chloride channels dramatically induces the expression of ClC-K current via insertion of ClC-K-barttin complexes into plasma membranes. We previously showed that stably expressed R8L barttin, a disease-causing missense mutant, is retained in the endoplasmic reticulum (ER) of Madin-Darby canine kidney (MDCK) cells, with the barttin β-subunit remaining bound to ClC-K α-subunits (Hayama A, Rai T, Sasaki S, Uchida S. Histochem Cell Biol 119: 485-493, 2003). However, transient expression of R8L barttin in MDCK cells was reported to impair ClC-K channel function without affecting its subcellular localization. To investigate the pathogenesis in vivo, we generated a knockin mouse model of Bartter syndrome that carries the R8L mutation. These mice display disease-like phenotypes (hypokalemia, metabolic alkalosis, and decreased NaCl reabsorption in distal tubules) under a low-salt diet. Immunofluorescence and immunoelectron microscopy revealed that the plasma membrane localization of both R8L barttin and the ClC-K channel was impaired in these mice, and transepithelial chloride transport in the thin ascending limb of Henle's loop (tAL) as well as thiazide-sensitive chloride clearance were significantly reduced. This reduction in transepithelial chloride transport in tAL, which is totally dependent on ClC-K1/barttin, correlated well with the reduction in the amount of R8L barttin localized to plasma membranes. These results suggest that the major cause of Bartter syndrome type IV caused by R8L barttin mutation is its aberrant intracellular localization.

Calcium-sensing receptor stimulates luminal K+-dependent H+ excretion in medullary thick ascending limbs of Henle's loop of mouse kidney

The calcium-sensing receptor (CaSR) is known well as a sensor of extracellular calcium for regulating parathyroid hormone secretion. CaSR is located along all nephron segments in the kidney. While hypercalcemia strongly enhances urinary acidification, the relationship between CaSR and acid-base metabolism in the kidney is still uncertain. In the present study, we examined whether CaSR activation caused acid secretion in the medullary thick ascending limb (mTAL), which is one of the major nephron segments involved in both mineral and acid-base regulation. The effects of a potent calcimimetic neomycin (Neo) on intracellular pH (pHi) were analyzed in the in vitro miroperfused mouse mTALs. The mTALs were incubated with 2,7-bis-(2-carboxyethyl)-5(6)-carboxyfluoresceine-acetoxymethylester (BCECF-AM) for microfluorescent pHi measurements. In HCO(3)(-)/CO(2)-buffered solution, the steady-state pHi was 7.17 +/- 0.01 (n = 19). Basolateral Neo at 0.4 mM in basolateral side significantly alkalinized the mTAL cells to 7.28 +/- 0.02 (n = 19), while Neo in the lumen had no effect on pHi. Neo in the basolateral side alkalinized the mTALs in the absence of ambient Na(+) and the presence of H(+)-ATPase inhibitor bafilomycin in the lumen, indicating that the effect of Neo is unrelated to Na(+)-dependent acid-base transporters such as Na(+)-H(+) exchangers and Na(+)-HCO(3)(-) cotransporter, or to luminal H(+)-ATPase. In contrast, the effect of Neo on pHi was inhibited by K(+) removal or treatment with specific H(+)-K(+)-ATPase (HKa) inhibitors, ouabain and Sch-28080, in the lumen. Our results suggest that hypercalcemia induces urinary acidification partly by stimulating luminal K(+)-dependent H(+)-excretion via CaSR in mouse mTALs.

Gestational length affects a change in the transepithelial voltage and the rNKCC2 expression pattern in the ascending thin limb of Henle's loop

To examine whether the functional and morphologic conversion of the neonatal ascending thin limb (ATL) of Henle's loop is related to gestational length, we evaluated the transepithelial voltages (Vts) of ATLs in perinatal mouse, hamster, rabbit, and rat kidneys. In isolated microperfused tubule preparations, Vts of neonatal ATLs were 23.8 +/- 1.4 in mouse, 25.7 +/- 2.2 in hamster, and 18.2 +/- 1.6 mV in rabbit. The influence of gestational length on the Vts and rat Na-K-Cl cotransporter (rNKCC2) expression pattern was also examined in perinatal rats subjected to a prolonged gestation due to either a daily s.c. injection of 5 mg progesterone or ligation of the extremities of the uterine horn. Vts of d 3 neonates were 2.9 +/- 1.0 (p < 0.0001 versus d 0); Vts of d 23 fetuses subjected to ligation were 4.9 +/- 0.8 (p < 0.005 versus d 0); and Vts of d 23 fetuses given progesterone were 3.4 +/- 1.7 mV (p < 0.001 versus d 0). rNKCC2 expression tended to disappear in the renal papillae of d 23 fetuses. Our data demonstrate that the perinatal conversion of the ATL is a phenomenon commonly observed among rodents; furthermore, it is dependent on the gestational length, but unrelated to the birth process.

Chloride-dependent intracellular pH regulation via extracellular calcium-sensing receptor in the medullary thick ascending limb of the mouse kidney

The extracellular calcium-sensing receptor (CaSR) located in either luminal or basolateral cell membranes of various types of renal tubules including proximal tubules, Henle's loop and collecting ducts has been thought to play a fundamental role in electrolyte metabolism. To further identify the physiological roles of the CaSR, we examined the effects of Ca(2+) and calcimimetics neomycin (Neo), gentamicin and gadolinium chloride (Gd(3+)) on the intracellular pH (pHi) of in vitro microperfused mouse medullary thick ascending limb (mTAL) cells of Henle's loop, by loading the cells with fluorescent pH indicator 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein and measuring the ratio of fluorescence emission at 530 nm after exciting the dye at 490 and 440 nm. In a steady-state condition in Hepes-buffered solution, the pHi in the mTALs was 7.29 +/- 0.04 (n = 9). A concentration of 200 micromol/l Neo in the basolateral side decreased the pHi after 1 min by -0.13 +/- 0.02 (n = 34, p < 0.0001). The other calcimimetics showed similar effects on pHi, whereas none of these calcimimetics in the lumen affected pHi. Na(+) removal or the inhibition of Na(+) and proton transport with amiloride, bumetanide, or bafilomycin did not eliminate the effect of Neo on pHi. On the other hand, Cl(-) removal clearly eliminated the Neo-induced pHi decrease (-0.06 +/- 0.01 vs -0.00 +/- 0.05 in Cl(-) removal, n = 4, p < 0.003). Thus, we have demonstrated for the first time that the CaSR is involved in the regulation of the pHi in the mTAL and requires Cl(-) to exert its effect.

Phylogenetic, ontogenetic, and pathological aspects of the urine-concentrating mechanism

The urine-concentrating mechanism is one of the most fundamental functions of avian and mammalian kidneys. This particular function of the kidneys developed as a system to accumulate NaCl in birds and as a system to accumulate NaCl and urea in mammals. Based on phylogenetic evidence, the mammalian urine-concentrating mechanism may have evolved as a modification of the renal medulla's NaCl accumulating system that is observed in birds. This qualitative conversion of the urine-concentrating mechanism in the mammalian inner medulla of the kidneys may occur during the neonatal period. Human kidneys have several suboptimal features caused by the neonatal conversion of the urine-concentrating mechanism. The urine-concentrating mechanism is composed of various functional molecules, including water channels, solute transporters, and vasopressin receptors. Abnormalities in water channels aquaporin (AQP)1 and AQP2, as well as in the vasopressin receptor V2R, are known to cause nephrogenic diabetes insipidus. An analysis of the pathological mechanism involved in nephrogenic diabetes insipidus suggests that molecular chaperones may improve the intracellular trafficking of AQP2 and V2R, and, in the near future, such chaperones may become a new clinical tool for treating nephrogenic diabetes insipidus.

Serum inhibitors for human mast cell growth: possible role of retinol

BACKGROUND

In vitro culture systems have been used to study the physiological and pathological characteristics of human mast cells. However, there are some differences in proliferation and maturation of mast cells between fetal bovine serum (FBS)-containing and serum-deprived cultures. Accordingly, we attempted to identify circulating factor(s) affecting the development of human mast cells.

METHODS

We measured the serum levels of retinol and several cytokines. To elucidate the antiproliferative effects of the serum, a retinoic acid receptor (RARalpha) antagonist and neutralizing antibodies against cytokines were used.

RESULTS

Similar to FBS, human serum dose-dependently suppressed the growth of tryptase+ cells from CD34+ cord blood cells or 20-week cultured mast cells under stimulation with stem cell factor (SCF). The serum-mediated inhibition might be based on a decline in proliferation rate. Among inhibitors for mast cell growth, retinol and transforming growth factor (TGF)-beta1 were present at high levels in human serum. In contrast with anti-TGF-beta1 antibody, an RARalpha antagonist counteracted the serum-induced suppression of human mast cell proliferation.

CONCLUSIONS

Our results suggest that retinol and its derivatives act as a circulating regulator for human mast cell growth. The RARalpha antagonist may be a useful tool to obtain higher numbers of mast cells in FBS-containing cultures.

Chitinases A, B, and C1 of Serratia marcescens 2170 produced by recombinant Escherichia coli: enzymatic properties and synergism on chitin degradation

To discover the individual roles of the chitinases from Serratia marcescens 2170, chitinases A, B, and C1 (ChiA, ChiB, and ChiC1) were produced by Escherichia coli and their enzymatic properties as well as synergistic effect on chitin degradation were studied. All three chitinases showed a broad pH optimum and maintained significant chitinolytic activity between pH 4 and 10. ChiA was the most active enzyme toward insoluble chitins, but ChiC1 was the most active toward soluble chitin derivatives among the three chitinases. Although all three chitinases released (GlcNAc)2 almost exclusively from colloidal chitin, ChiB and ChiC1 split (GlcNAc)6 to (GlcNAc)3, while ChiA exclusively generated (GlcNAc)2 and (GlcNAc)4. Clear synergism on the hydrolysis of powdered chitin was observed in the combination between ChiA and either ChiB or ChiC, and the sites attacked by ChiA on the substrate are suggested to be different from those by either ChiB or ChiC1.

Identification of serine138 residue in the 4-residue segment K135K1361137S138 of LukS-I component of Staphylococcus intermedius leukocidin crucial for the LukS-I-specific function of staphylococcal leukocidin

Luk-I produced by Staphylococcus intermedius was found to be a new member of the staphylococcal bi-component pore-forming toxin family, in which staphylococcal leukocidin, Panton-Valentine leukocidin, and gamma-hemolysin are included. Luk-I consists of LukS-I and LukF-I. From the deduced amino acid sequence of LukS-I, a 4-residue sequence, K135K1361137S138, at the root of the stem region was found to be identical with that of the phosphorylated segment of a protein phosphorylated by protein kinase A. A mutant of LukS-I (MLSI-SA), in which the Ser138 residue was replaced by an alanine residue, was created, purified, and assayed for its leukocytolytic and pore-forming activities with LukF-I. Both LukS-I and MLSI-SA formed a ring-shaped complex with LukF-I on rabbit erythrocytes and human polymorphonuclear leukocytes (HPMNLs) membrane. However, MLSI-SA showed no leukocytolytic activity with LukF-I. LukS-I was phosphorylated by protein kinase A in the presence of [gamma-32P] ATP in a cell-free system, but MLSI-SA was not phosphorylated significantly. A potent and selective inhibitor of protein kinase A (N-[2(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide (H-89)) showed 50% inhibition of the Luk-I-induced cell lysis at 0.5 nM. Thus, it is concluded that the phosphorylation of the Ser138 residue in the 4-residue segment K135K1361137S138 of LukS-I is important for the leukocytolysis of HPMNLs.

Expression of C-C chemokine TARC in human nasal mucosa and its regulation by cytokines

BACKGROUND

Although interleukin (IL)-4 and IL-5 have been demonstrated to play a critical role in the pathophysiology of allergic diseases such as allergic rhinitis, the mechanism that causes the predominance of Th2 lymphocytes has yet to be clarified. Thymus and activation-regulated chemokine (TARC) has been known to facilitate the recruitment, activation and development of Th2 polarized cells, leading investigators to suggest a role for TARC in the development of Th2 responses.

OBJECTIVE

To gain a better understanding of the role of TARC in the pathogenesis of allergic rhinitis we investigated the cellular sources of this chemokine in nasal mucosa. In addition, the effect of cytokines on TARC production has been investigated.

METHODS

The expression of TARC in human nasal mucosa was assessed by immunohistochemistry. To study the effect of cytokines on TARC production, epithelial cells, endothelial cells and fibroblasts, isolated from inferior nasal mucosa samples, were stimulated by a variety of cytokines including IL-4, IL-13, tumour necrosis factor (TNF)-alpha and interferon (IFN)-gamma.

RESULTS

Epithelial cells in nasal mucosa in subjects with allergic rhinitis expressed higher signal level than those in non-allergy patients. Combined stimulation with IL-4 and TNF-alpha, as well as IL-13 and TNF-alpha, synergistically induced TARC expression in epithelial cells. Furthermore, the amount of TARC induced by these cytokines was higher in epithelial cells obtained from patients with allergic rhinitis than in those from non-allergic patients.

CONCLUSION

These results demonstrate a crucial role of nasal epithelial cells in the expression of TARC, and that Th2 cytokine IL-4 and IL-13 may promote Th2 responses by inducing TARC production from epithelial cells.

Serum anti-Lewis X antibody is associated with VacA seropositivity but not atrophic gastritis in patients with Helicobacter pylori infection

OBJECTIVES

Lipopolysaccharides of Helicobacter pylori have an antigenic structure that mimics Lewis X occurring in gastric mucosa. The pathogenic role of antigenic mimicry in H. pylori-induced gastritis has been of recent interest. The aim of this study was to examine the relevance of anti-Lewis X antibody in the development of atrophic gastritis in H. pylori infection.

METHODS

A total of 72 patients were studied. Serum samples were collected to measure IgG antibodies to H. pylori, CagA, VacA and Lewis X. Biopsy specimens were obtained from the antrum and the corpus to examine the grade and the type of atrophic gastritis.

RESULTS

Mean anti-Lewis X antibody titres were higher in 38 VacA-seropositive patients than in 13 seronegative patients (P < 0.05). The difference was not significant between patients with diffuse-type atrophic gastritis and those with multi-focal type. No significant correlation was observed between the titre of anti-Lewis X antibody and the grade of glandular atrophy, whereas CagA seropositivity was associated with glandular atrophy.

CONCLUSIONS

Anti-Lewis X antibody may play a role in persistent gastric inflammation, particularly in VacA-seropositive H. pylori infection. However, anti-Lewis X antibody does not seem itself to be associated with atrophic gastritis in patients with H. pylori infection.

[The occlusal contact mode during lateral excursion]

The purpose of this study is to clarify the occlusal contact mode between the upper and lower molars on the working side of group function occlusion during lateral excursion. After the intercuspal position (IP) and two lateral positions (L1, the middle point between IP and L2; L2, the edge-to-edge occlusal position of the molars) on the Gothic arch were defined, occlusal contact relations in these three occlusal positions were recorded, using black silicone. Digital data of real occlusal contacts and visualized data of close (less than 30 microns) occlusal areas, by computer image processing, were analyzed. The conclusions are as follows: 1. Although the numbers of real occlusal contacts and the visualized occlusal area tend to decrease toward L2 during lateral excursion, the former, in some cases, goes up and down. 2. Functional cusps play an important part in occlusal contact at the intercuspal position. 3. Occlusal contact points are on the functional cusps of the upper and lower molars, which can be clinically regarded as certain points, and these points slide on the inclining non-functional cusps of antagonistic teeth during lateral excursion. 4. Each upper and lower molar has 2 to 6 occlusal contact points near the top functional cusps at the intercuspal position, and some of them contact continuously during lateral excursion.

Soluble CD30 is more relevant to disease activity of atopic dermatitis than soluble CD26

It is suggested that CD30 and CD26 are surface molecules expressed on activated Th2 and Th1 cells, respectively. We examined plasma levels of soluble CD26 (sCD26) and sCD30 in patients with atopic dermatitis (AD) when their eruptions were aggravated and in non-atopic healthy controls, and then analysed the possible correlation between these values and the levels of several clinical markers. The plasma levels of both sCD30 and sCD26 were significantly higher in AD patients than in controls, both in exacerbation status and after conventional treatment. Multiple regression analyses showed that plasma sCD30 was a much better predictor of the levels of serum IgE, serum LDH and plasma sCD25, and the area and the score of AD eruption than sCD26, although elevated levels of both sCD30 and sCD26 are associated with these clinical predictors of AD. Importantly, sCD30 plasma levels decreased significantly in AD patients after conventional treatment, while no significant transition was noted in the concentration of sCD26. Moreover, a significant reduction of sCD30 levels was observed in the group of patients whose eruption score was reduced > 50%, whereas it was not in those < 50%. These findings provide evidence that the successful treatment of AD is associated with down-activation of Th2.

DNA length dependence of the single-strand annealing pathway and the role of Saccharomyces cerevisiae RAD59 in double-strand break repair

A DNA double-strand break (DSB) created by the HO endonuclease in Saccharomyces cerevisiae will stimulate recombination between flanking repeats by the single-strand annealing (SSA) pathway, producing a deletion. Previously the efficiency of SSA, using homologous sequences of different lengths, was measured in competition with that of a larger repeat further from the DSB, which ensured that nearly all cells would survive the DSB if the smaller region was not used (N. Sugawara and J. E. Haber, Mol. Cell. Biol. 12:563-575, 1992). Without competition, the efficiency with which homologous segments of 63 to 205 bp engaged in SSA was significantly increased. A sequence as small as 29 bp was used 0.2% of the time, and homology dependence was approximately linear up to 415 bp, at which size almost all cells survived. A mutant with a deletion of RAD59, a homologue of RAD52, was defective for SSA, especially when the homologous-sequence length was short; however, even with 1.17-kb substrates, SSA was reduced fourfold. DSB-induced gene conversion also showed a partial dependence on Rad59p, again being greatest when the homologous-sequence length was short. We found that Rad59p plays a role in removing nonhomologous sequences from the ends of single-stranded DNA when it invades a homologous DNA template, in a manner similar to that previously seen with srs2 mutants. Deltarad59 affected DSB-induced gene conversion differently from msh3 and msh2, which are also defective in removing nonhomologous ends in both DSB-induced gene conversion and SSA. A msh3 rad59 double mutant was more severely defective in SSA than either single mutant.

Serum anti-Lewis X antibody is not elevated in patients with gastric cancer infected with Helicobacter pylori

Lipopolysaccharides of Helicobacter pylori express Lewis X similar to that occurring in gastric mucosa. Patients infected with H. pylori produce anti-Lewis X antibodies. The aim of this study was to examine whether anti-Lewis X antibody was associated with the development of gastric cancer, particularly intestinal type cancer. Serum sample was collected from 98 patients with early gastric cancer and 98 gender- and age-matched control subjects who underwent endoscopy. Histologically, 77 cancers were of the intestinal type. Titers of anti-H. pylori and anti-Lewis X immunoglobulin G (IgG) antibodies were assayed by enzyme-linked immunosorbent assay. The mean titer of Lewis X antibody was 0.097 in patients with gastric cancer and 0.110 in matched control subjects (not significant). In 72 H. pylori-seropositive patients with intestinal type cancer and their matched H. pylori-seropositive controls, mean titer was 0.115 and 0.107, respectively (not significant). The odds ratio for the risk of gastric cancer if Lewis X antibody was high titer was 0.93 (95% CI 0.43-2.00). The odds ratio for the risk of intestinal type gastric cancer in patients with H. pylori infection if Lewis X antibody was high titer was 1.10 (95(% CI, 0.46-2.62). Anti-Lewis X antibody does not seem to be associated with the development of gastric cancer, even the intestinal type cancer.

Competition between copper and silver in Fischer rats with a normal copper metabolism and in Long-Evans Cinnamon rats with an abnormal copper metabolism

Long-Evans Cinnamon (LEC) rats inherently lacking in serum ceruloplasmin (CP) activity and biliary Cu excretion were established from a closed colony of Long-Evans rats. These deficiencies, linked to a dysfunction of P-type ATPase, stimulate deposition of Cu and then of Cu metallothionein (MT) in the liver. Male LEC and Fischer rats were injected subcutaneously with Ag (AgNO3), which is an antagonist to Cu. They were operated on 24 h after the injection while under anesthesia. Total uptake of Ag into the liver was not stimulated, but its uptake into the MT fraction increased significantly in the LEC rats. Ag injection notably decreased the activity of serum CP in the Fischer rats, but not in the LEC rats. The decrease was accompanied by a reduction of serum Cu. In Fischer rat serum treated with Ag, Ag was detected mainly in the albumin region and partly in the CP fraction. In LEC rat serum, however, the Ag concentration was about 1/20 of that in the Fischer rats, and Ag was not detected in the CP fraction. Ag injection decreased the biliary excretion of Cu in the Fischer rats (0.183-0.052 microg Cu/20 min sampling), but not in the LEC rats (0.014-0.014 microg Cu/20 min sampling). On the other hand, biliary excretion of Ag was much greater in the Fischer rats (1.25 microg Ag/20 min) than in the LEC rats (0.04 microg Ag/20 min). Our results suggest that uptake of Ag into the liver is not dependent on the hepatic Cu content and status, but that biliary excretion of Ag from the liver is affected by these. Hepatic MT is not a transporter of hepatobiliary excretion of Cu and Ag. It seems likely that, unlike Cu excretion, Ag is excreted by not only the CP route but also by another route into the serum. Ag may compete with Cu in the uptake into CP (conversion of apo-CP to holo-CP).

The Saccharomyces cerevisiae Msh2 mismatch repair protein localizes to recombination intermediates in vivo

Mismatch repair proteins act during double-strand break repair (DSBR) to correct mismatches in heteroduplex DNA, to suppress recombination between divergent sequences, and to promote removal of nonhomologous DNA at DSB ends. We investigated yeast Msh2p association with recombination intermediates in vivo using chromatin immunoprecipitation. During DSBR involving nonhomologous ends, Msh2p localized strongly to recipient and donor sequences. Localization required Msh3p and was greatly reduced in rad50delta strains. Minimal localization of Msh2p was observed during fully homologous repair, but this was increased in rad52delta strains. These findings argue that Msh2p-Msh3p associates with intermediates early in DSBR to participate in the rejection of homeologous pairing and to stabilize nonhomologous tails for cleavage by Rad1p-Rad10p endonuclease.

The third chitinase gene (chiC) of Serratia marcescens 2170 and the relationship of its product to other bacterial chitinases

The third chitinase gene (chiC) of Serratia marcescens 2170, specifying chitinases C1 and C2, was identified. Chitinase C1 lacks a signal sequence and consists of a catalytic domain belonging to glycoside hydrolase family 18, a fibronectin type III-like domain (Fn3 domain) and a C-terminal chitin-binding domain (ChBD). Chitinase C2 corresponds to the catalytic domain of C1 and is probably generated by proteolytic removal of the Fn3 and ChBDs. The loss of the C-terminal portion reduced the hydrolytic activity towards powdered chitin and regenerated chitin, but not towards colloidal chitin and glycol chitin, illustrating the importance of the ChBD for the efficient hydrolysis of crystalline chitin. Phylogenetic analysis showed that bacterial family 18 chitinases can be clustered in three subfamilies which have diverged at an early stage of bacterial chitinase evolution. Ser. marcescens chitinase C1 is found in one subfamily, whereas chitinases A and B of the same bacterium belong to another subfamily. Chitinase C1 is the only Ser. marcescens chitinase that has an Fn3 domain. The presence of multiple, divergent, chitinases in a single chitinolytic bacterium is perhaps necessary for efficient synergistic degradation of chitin.

Separation-of-function mutations in Saccharomyces cerevisiae MSH2 that confer mismatch repair defects but do not affect nonhomologous-tail removal during recombination

Yeast Msh2p forms complexes with Msh3p and Msh6p to repair DNA mispairs that arise during DNA replication. In addition to their role in mismatch repair (MMR), the MSH2 and MSH3 gene products are required to remove 3' nonhomologous DNA tails during genetic recombination. The mismatch repair genes MSH6, MLH1, and PMS1, whose products interact with Msh2p, are not required in this process. We have identified mutations in MSH2 that do not disrupt genetic recombination but confer a strong defect in mismatch repair. Twenty-four msh2 mutations that conferred a dominant negative phenotype for mismatch repair were isolated. A subset of these mutations mapped to residues in Msh2p that were analogous to mutations identified in human nonpolyposis colorectal cancer msh2 kindreds. Approximately half of the these MMR-defective mutations retained wild-type or nearly wild-type activity for the removal of nonhomologous DNA tails during genetic recombination. The identification of mutations in MSH2 that disrupt mismatch repair without affecting recombination provides a first step in dissecting the Msh-effector protein complexes that are thought to play different roles during DNA repair and genetic recombination.

Iron depletion prevents adenine nucleotide decomposition and an increase of xanthine oxidase activity in the liver of the Long Evans Cinnamon (LEC) rat, an animal model of Wilson's disease

The Long Evans Cinnamon (LEC) rat, which accumulates excess Cu in the liver as in patients with Wilson's disease, is a mutant strain displaying spontaneous hepatitis. It was reported that Fe, like Cu, increases in the liver and that the severity of hepatitis is modified by Fe in the diet. In this experiment, oxidative stress increased by Fe was investigated before the onset of hepatitis. To examine the effect of Fe on the progress into hepatitis, LEC female rats were fed an Fe-regular (Fe 214 microg/g; Fe(+) group) or an Fe-restricted (Fe 14 microg/g; Fe(-) group) diet from 53 days of age for 35 days. Fischer rats were also fed as control animals. Adenine nucleotide decomposition was determined as an index of oxidative stress based on xanthine oxidase activity. The size of the hepatic pool of adenine nucleotides (ATP+ADP+AMP) was significantly smaller in LEC rats than Fischer rats. The energy charge (ATP+0.5ADP)/(ATP+ADP+AMP) was smaller in Fe(+) groups than in Fe(-) groups. In the LEC rat liver, the Fe concentration in the Fe(+) group was 160% of that in Fe(-) group and the correlation coefficient between the hepatic Fe concentration and the energy charge was significant. In this strain, an increase of xanthine oxidase activity resulted in an increase of xanthine, an oxidized metabolite of hypoxanthine in the liver. The results suggest the involvement of the Fe in the progression into hepatitis in the LEC rat, even if the dietary Fe concentration is similar to that of commercial diet.