Immunolocalization of cellular glutathione peroxidase in adult rat lungs and quantitative analysis after postembedding immunogold labeling

To determine the distribution of cellular glutathione peroxidase in rat lungs, the tissues were stained immunohistochemically. Quantitative analysis was performed in certain cell types of alveolar linings, after the ultrathin sections were stained by a postembedding immunogold technique. Immunoblot analysis revealed that homogenates of rat liver, heart, and lungs all gave a single band. Under the light microscope, the following tissues were stained intensely: epithelial cells, smooth muscle cells and glands of bronchi and bronchioles, type II alveolar cells, and alveolar macrophages. Under immunoelectron microscopy, type II alveolar cells and macrophages were abundant in mitochondria. The mitochondria, nucleus, and cytoplasm of macrophages were labeled almost twice as densely as the respective compartments of type II alveolar cells. Within cell types, the mitochondria were labeled twice as densely as the nuclei. The other particles were less than half as densely labeled as the nuclei. The labeling was slightly less dense in the cytoplasm than in the nucleus. The present study revealed that glutathione peroxidase occurred predominantly in the epithelial linings and metabolically active sites in rat lungs. The tissues that were previously found to be rich in superoxide dismutases were also rich in glutathione peroxidase.

A polyreactive human anti-lipid A monoclonal antibody having cross reactivity to polysaccharide portions of Pseudomonas aeruginosa lipopolysaccharides

A hybridoma cell line producing a human anti-lipid A monoclonal antibody (mAb), FKF-IF3 (IgM (k)) was obtained by cell fusion of Epstein-Barr virus-transformed cells and mouse myeloma. The mAb bound to not only Gram-negative bacterial lipid A, but also to polysaccharide portions of Pseudomonas aeruginosa lipopolysaccharides (LPS). The mAb seemed to recognize two distinct regions of P. aeruginosa LPS other than lipid A, namely the outer core regions of some serotype strains and the O-polysaccharide region of serotype A strains. The mAb cross-reacted with N-acetyl-beta-glucosamine-conjugated bovine serum albumin, N-acetyl-beta-galactosamine-conjugated bovine serum albumin, myosin and actin, but not with other autoantigens such as ss- and ds-DNA, cardiolipin and glycosaminoglycans. The mAb conferred protective activity against a mouse pseudomonal infection model. The evidence suggested that the mAb was a naturally occurring polyspecific antibody that participated in defense against pseudomonal infections.

Intracellular interaction of collagen-specific stress protein HSP47 with newly synthesized procollagen

Heat shock protein 47 (HSP47), a collagen-specific stress protein, has been postulated to be a collagen-specific molecular chaperone localized in the ER. We previously demonstrated that HSP47 transiently associated with newly synthesized procollagen in the ER (Nakai, A., M. Satoh, K. Hirayoshi, and K. Nagata. 1992. J. Cell Biol. 117:903-914). In the present work, we examined the location where HSP47 binds to and dissociates from newly synthesized procollagen within the cells, and whether HSP47 associates with nascent single procollagen polypeptide chains and/or with mature triple-helix procollagen. This was accomplished by biochemical coprecipitation with anti-HSP47 and anticollagen antibodies, combined with pulse-label and chase experiments in the presence or absence of various inhibitors for protein secretion, as well as by confocal laser microscopic observation of the cells double stained with both antibodies. We further examined whether the RDEL (Arg-Asp-Glu-Leu) sequence at the COOH terminus of HSP47 can act as an ER-retention signal, as the KDEL sequence does. When the secretion of procollagen was inhibited by the presence of alpha, alpha'-dipyridyl, an iron chelator that inhibits procollagen triple-helix formation, or by the presence of brefeldin A. which inhibits protein transport between the ER and the Golgi apparatus, procollagen was found to be bound to HSP47 during the chase period in the intermediate compartment. In contrast, the dissociation of procollagen chains from HSP47 was not inhibited when procollagen secretion was inhibited by monensin or bafilomycin A1, both of which are known to be inhibitors of post-cis-Golgi transport. These findings suggest that HSP47 and procollagen dissociated between the post-ER and the cis-Golgi compartments. HSP47 was shown to bind to nascent, single-polypeptide chains of newly synthesized procollagen, as well as to the mature triple-helix form of procollagen. HSP47 with the RDEL sequence deleted was secreted out of the cells, which suggests that the RDEL sequence actually acts as an ER-retention signal, as the KDEL sequence does. This secreted HSP47 did not acquire endoglycosidase H resistance. The biological significance of the interaction between HSP47 and procollagen in the central secretory pathway, as well as possible mechanisms for this pathway, will be discussed.

Mother-to-infant transmission of hepatitis C virus in human immunodeficiency virus-coinfected mother: a case report

We report a case of vertical transmission of HCV in a mother infected with both HCV and HIV. Our case suggests that coinfection with HIV, by causing an immune dysfunction, might be one of the risk factors for the transmission of HCV.

Suppression of azoxymethane-induced aberrant crypt foci in rat colon by nimesulide, a selective inhibitor of cyclooxygenase 2

Non-steroidal anti-inflammatory drugs, such as piroxicam and sulindac, are known to inhibit development of aberrant crypt foci (ACF) and cancer in the colon. However, these agents cause gastrointestinal side-effects. Nimesulide is a selective inhibitor of cyclooxygenase 2 and has been shown to have a more potent anti-inflammatory action than piroxicam, but be less ulcerogenic and, therefore, a potentially more useful chemopreventive agent. To assess this possibility the inhibitory effects of nimesulide on the formation of ACF induced by azoxymethane in rat colon were investigated, and compared with those of piroxicam and sulindac. Male F344 rats were treated s.c. with 15 mg/kg body weight azoxymethane once a week for 2 weeks and given 50, 100 or 200 ppm nimesulide, 200 ppm piroxicam, or 200 ppm sulindac in their diet from the day before the first carcinogen treatment until the end of the experiment at week 4. At this time, nimesulide at doses of 50, 100 and 200 ppm had reduced the numbers of azoxymethane-induced ACF to 75%, 71% and 65% respectively compared to the control. The number of azoxymethane-induced ACF per colon in the group given 200 ppm nimesulide was almost the same as in those given 200 piroxicam, and lower than that in the group given 200 ppm sulindac. These results suggest that nimesulide, a selective cyclooxygenase 2 inhibitor, warrants attention as a candidate for chemopreventive agent with low toxicity, active against colon carcinogenesis.

Lung cancer producing interleukin-6

A patient with complaints of high fever and left shoulder pain was found to have a large mass in the left upper lobe on chest roentgenogram. Laboratory evaluation revealed marked thrombocytosis, hypoalbuminemia, and increased serum concentrations of CRP, fibrinogen and interleukin-6 (IL-6). A transcutaneous biopsy specimen revealed large cell carcinoma. Tumor production of IL-6 was confirmed by immunohistochemical staining with an anti-human IL-6 monoclonal antibody (MH60).

Demonstration of mother-to-infant transmission of Staphylococcus aureus by pulsed-field gel electrophoresis

We assessed mother-to-infant transmission of Staphylococcus aureus. Anterior nares swabs of 466 pregnant women, vaginal swabs of 305 of these women and anterior nares swabs of 305 6-day-old infants were examined for the presence of S. aureus. The results showed that 7.5% of the vaginal swabs from the pregnant women and 10.1% of the anterior nares swabs from the infants were positive for S. aureus. Six of the 466 pregnant women (1.3%) and 12 of the 305 infants (3.9%) carried methicillin-resistant S. aureus (MRSA) in the anterior nares site, but none of the vaginal specimens were positive for MRSA. Analysis of SmaI digested chromosomal DNA analysis using pulsed-field gel electrophoresis (PFGE) showed that methicillin-sensitive S. aureus (MSSA) strains obtained from four pairs of pregnant women and their infants were completely identical, which strongly suggests [correction of suggesting] mother-to-infant transmission of S. aureus.

CONCLUSION

This study elucidated the prevalence of S. aureus carriage among pregnant women and newborn infants. Mother-to-infant infection of S. aureus was demonstrated phenotypically and genetically. PFGE is a useful tool to detect infection routes including mother-to-infant infection.

T-cell lymphoma presenting with pericardial and pleural effusion as the initial and primary lesion: cytogenetic and molecular evidence

A 90-year-old woman was admitted with progressive dyspnea. Chest roentgenogram and computed tomography revealed a massive pericardial effusion and bilateral pleural effusion, but no lymphomatous lesion was seen. A diagnosis of malignant lymphoma was made by cytological and immunological studies of the cells obtained from the pericardial effusion. Chromosome analysis showed a clonal abnormality and T-lineage clonality was determined by the rearrangement of the T-cell receptor gamma gene. The patient achieved remission with chemotherapy, but she later relapsed, with right pleural effusion, and died. She exhibited no lymphomatous features throughout the clinical course, indicating the possibility of malignant lymphoma originating from the pericardium and/or pleura.

[A case of staphylococcal scalded skin syndrome caused by exfoliative toxin-B producing MRSA]

We experienced a 6 month-old infant who suffered from staphylococcal scalded skin syndrome (SSSS), whose mother used steroid ointment for the infant's erythematous skin rash for 2 days. On the 3rd day, the infant was admitted to our hospital with fever, erythema on the trunk and extremities, and flaccid blisters and erosions at periorificial areas and the neck. Nikolsky's sign was positive. S. aureus was cultured from the throat, conjunctival inflammatory lesion and exudates. The biological characteristics of the isolates were coagulase type I, enterotoxin-nonproducing, TSST-1-nonproducing, protease pattern: D type, and plasmid profile: 563 kbp. The investigation of exfoliative toxin (ET) revealed negative for ET-A but positive for ET-B, proved by polymerase chain reaction (PCR). The isolated strain of S. aureus was demonstrated to be methicillin-resistant (MRSA), which was further defined to be positive for mec A gene by PCR method. It will be possible for such toxigenic ET-B producing MRSA to gain the dominant status in NICU or closed areas.

Alterations of CDKN2 gene structure in childhood acute lymphoblastic leukemia: mutations of CDKN2 are observed preferentially in T lineage

We analyzed homozygous deletions and mutations of the CDKN2(p16(INK4A)/MTS1) gene, using polymerase chain reaction and Southern blot analysis, in 120 children with acute lymphoblastic leukemia (ALL). Homozygous deletion was found in 17 of 89 (19%) precursor B-ALL patients, in 11 of 24 (46%) T-ALL patients, and in 0 of 7 other phenotype ALL patients. After excluding 28 (23%) patients who showed a homozygous deletion of CDKN2, we found that three patients (3%) had mutation at exon 2 of CDKN2 using PCR-SSCP and sequencing strategy. One had a CGA to TGA nonsense mutation (Arg to stop) at codon 72, one had a 1-bp deletion at codon 117, and the third had a 2-bp deletion at codon 70, resulting in frameshifts in the two latter patients. All three of these patients were T phenotype ALL, and the incidence of mutation in the 24 T-ALL patients examined was 13%. In contrast, no mutation was detected in the remaining patients with precursor-B or other type ALL (0/96). Our results suggest that mutational inactivation of the CDKN2 gene may contribute to the leukemogenic growth, especially in some patients with T-ALL.

Cross-linking of the ninth consensus repeat domain of P-selectin (GMP-140, CD62P) with a monoclonal antibody enhanced leukocyte adhesive activity

P-selectin (GMP-140, CD62P) is a member of the selectin family of cell adhesion molecules expressed on the cell surface of platelets and endothelial cells, which mediates leukocyte adhesion via carbohydrate ligands. We now report that a monoclonal antibody (mAb), recognizing the ninth consensus repeat domain of the human P-selectin molecule, enhanced the adhesion activity of neutrophils to platelets, whereas the monovalent Fab fragment of the mAb did not exert this effect. The enhancement by the mAb was thought to result from cross-linking of the P-selectin molecules. The results indicated that cross-linking adjacent to the transmembrane domain of P-selectin enhanced the cell adhesion activity.

[A case of tuberculous meningitis followed by tuberculoma with pan-hypopituitarism]

We reported a case who suffered from tuberculous meningitis at 10 months of age, and progressed to basal tuberculoma despite intensive drug therapy with isoniazid, rifampin, and streptomycin. Pan-hypopituitaliam due to basal tuberculoma was effectively replaced by the administration of anti-diuretic hormone (DDAVP) and levothyroxine sodium. Basal tuberculoma was finally removed by surgical operation. Histopathological examination of the tuberculoma revealed Mycobacterium tuberculosis and Langhans giant cells. During the 6 years after the operation, her growth rate was found to be retarded, and the administration of human growth hormone was started. Remarkable catch-up growth was demonstrated. We like to emphasize that infantile tuberculosis, mostly a result of intafamilial transmission, may manifest meningitis in the early phase of the disease, and it sometimes progresses to basal tuberculoma unresponsive to anti-mycobacterial drug therapy.

Peroxisome assembly factor-2, a putative ATPase cloned by functional complementation on a peroxisome-deficient mammalian cell mutant

Rat peroxisome assembly factor-2 (PAF-2) cDNA was isolated by functional complementation of peroxisome deficiency of a mutant CHO cell line, ZP92, using transient transfection assay. This cDNA encodes a 978-amino acid protein with two putative ATP-binding sites. PAF-2 is a member of a putative ATPase family, including two yeast gene products essential for peroxisome assembly. A stable transformant of ZP92 with the cDNA was morphologically and biochemically restored for peroxisome biogenesis. Fibroblasts derived from patients deficient in peroxisome biogenesis (complementation group C) were also complemented with PAF-2 cDNA, indicating that PAF-2 is a strong candidate for the pathogenic gene of group C peroxisome deficiency.

Autophagic death after cell cycle arrest at the restrictive temperature in temperature-sensitive cell division cycle and secretory mutants of the yeast Saccharomyces cerevisiae

When virgin temperature-sensitive mutant cdc28 cells of the yeast Saccharomyces cerevisiae were incubated at restrictive temperatures, they continued to grow, reaching a maximum of 3.3-fold the original size after 24 h. The protein and RNA levels increased during the first 24 h, then gradually decreased. The cells that reached the maximal size lost proliferative activity and synthesized less protein. After a 72-h incubation, cellular components, protein, RNA and DNA, were progressively degraded, resulting in extensive fragmentation within 7 days. Light and electron microscopic observation revealed that cdc28 cells incubated at the restrictive temperature for 24 h were enriched with double-unit membranes in the cytoplasm, and the vacuoles were filled with autophagic body-like structures. After 7 days most cellular contents were lost, and the membrane systems were fragmented. The protein synthesis inhibitor cycloheximide added at 24 h inhibited degradation of protein for at least 7 days suggesting that protein synthesis was involved in the activation of autophagic death. All other temperature-sensitive cdc and secretory (sec) mutants tested showed similar morphological changes when arrested in the cell division cycle at the restrictive temperature. In contrast, the temperature-insensitive wild-type cells grew normally at 38 degrees C and only a few percent of them underwent autolysis 7 days after transfer to the stationary phase. These results suggested that the yeast cells underwent autophagic death when arrested at any stage of the cell division cycle, whereas those arrested at the stationary phase rarely underwent autophagic death.

Identification of outer membrane proteins as target antigens of Pseudomonas aeruginosa Homma serotype M

Pseudomonas aeruginosa is routinely serotyped in Japan by using the Homma scheme. The serotypes (O serotypes) are based on the chemical structure of the O-polysaccharide portion of the lipopolysaccharide (LPS). However, the nature of the Homma serotype M antigen has remained obscure because strains classified as serotype M usually have the rough phenotype. I characterized the target antigen of serotype M. The results of Western blotting (immunoblotting) showed that commercially available typing monoclonal antibody (MAb) against serotype M specifically bound to outer membrane protein (Opr) G and that typing rabbit antiserum specific for serotype M mainly contained antibodies against Oprs F and H2. These Oprs were distributed among all P. aeruginosa strains tested, including the serotype standard, serotype M and nontypeable strains, and a series of LPS-core-defective mutants derived from strain PAC1. However, the rough mutants derived from strain PAC1 agglutinated with the anti-serotype M antibodies, whereas the smooth strains did not. LPS preparations from serotype M strains possessed few or no polysaccharide chains. These strains had higher levels of binding activity with anti-serotype M MAb, as well as with anti-lipid A MAb, which specifically bound to the cell surface of the rough-natured gram-negative bacterial strains with high activity. The anti-serotype M antiserum also contained rough-LPS-specific antibodies, but the epitope was distributed among only a few strains. The results suggested that the Oprs acted as the serotype M antigen and that LPS did not. In conclusion, the rough strains agglutinated with anti-Opr antibodies and were distinguished as serotype M from the smooth strains of other serotypes, because the antibodies were accessible to the cell surface lacking O polysaccharides. I supposed that Homma serotype M is an index of the rough nature of P. aeruginosa strains rather than one of the O serotypes.

Role of LPS length in clearance rate of bacteria from the bloodstream in mice

Strains of Pseudomonas aeruginosa isolated from patients with cystic fibrosis (CF) never spread systemically. This may be due to serum sensitivity since these strains are very sensitive to complement-mediated bactericidal activity. A serum-resistant mutant, P. aeruginosa TUM3 HSR, was obtained from serum-sensitive strain TUM3 from a CF patient in order to clarify the mechanism of failure of systemic spread. LPS profiles on silver-stained gels and immunological analysis revealed that a long O-polysaccharide side chain was overproduced on the LPS molecules of TUM3 HSR as compared with the LPS of TUM3. The clearance rate from the bloodstream in mice was compared in the two strains. The number of TUM3 bacteria in 1 ml of blood, 10 min after injection into the tail vein, significantly decreased from 1.7 x 10(8) to 3.7 x 10(5) c.f.u. ml-1. In contrast, TUM3 HSR was not eliminated during the same period (decrease from 1.9 x 10(8) to 3.4 x 10(7) c.f.u. ml-1). Interestingly, these isogenic strains were not killed by 40% murine serum, probably reflecting immaturity of the complement-mediated killing system in mice. These results pointed to a correlation between LPS structure and blood clearance rate in mice. This was confirmed by examining blood clearance kinetics using the smooth-LPS strain Salmonella typhimurium LT2 and LPS-deficient mutants derived from it. S. typhimurium LT2 resisted blood clearance while the LPS-deficient mutants were cleared rapidly. None of the S. typhimurium strains were killed by murine serum. The number of P. aeruginosa TUM3 and S. typhimurium LPS-deficient mutants trapped in the liver following injection into the peripheral circulation was greater than that of their counterparts.(ABSTRACT TRUNCATED AT 250 WORDS)

Epidemiological analysis of strains of methicillin-resistant Staphylococcus aureus (MRSA) infection in the nursery; prognosis of MRSA carrier infants

Forty-five neonates who carried methicillin-resistant Staphylococcus aureus (MRSA) were studied. Retrospective molecular analysis using pulsed-field gel electrophoresis showed three separate MRSA epidemics in the nursery. Strains of MRSA isolated from the neonates were also isolated from the hospital environment and health care providers. Clinical manifestations included skin pustules (eight patients), conjunctivitis (four patients), or other minor infections (two patients). No neonate developed systemic infection. The prevalence of MRSA decreased with age. At one year, three (14.3%) of 21 infants that had carried MRSA at six days remained carriers and only two (1.1%) of 180 infants in a control 'S. aureus-negative at six days' group carried MRSA.

Relaxation effect of an audiovisual system on dental patients. Part 2. Palus-amplitude

Dental care services include relaxation of patients to reduce their displeasure at and tension during treatment. For this purpose, it is common to use audio or audiovisual programs, that is, to let them listen to music or watch TV. However, the former utilizes only the auditory sense, and the latter is disadvantageous in that a TV set is a rather large-scale unit. In the present study, we determined the relaxation effect of an audiovisual instrument on dental patients. The instrument, which gives virtual vision, was composed of a lightweight eyeset of the snow goggle type that has a built-in TV screen, with earphone and accessories. The relaxation effect was determined using a polygraph.

Immunocytochemical localization of L-alpha-hydroxyacid oxidase in dense bar of dumb-bell-shaped peroxisomes of monkey kidney

Localization of the B of L-alpha hydroxyacid oxidase (HOX-B) in monkey kidney peroxisomes was investigated by immunoelectron microscopic techniques. Kidneys of Japanese monkeys, Macaca fuscata, were fixed with 4% paraformaldehyde + 0.25% glutaraldehyde and embedded in LR White resin. Thin sections were stained for HOX-B and catalase by the immunogold technique. HOX-B was localized in the marginal plates of normal peroxisomes and the dense bar of dumb-bell-shaped peroxisomes. Catalase was detected in the matrix of normal peroxisomes and in the terminal dilatations of dumb-bell-shaped peroxisomes. There were no gold particles indicating presence of catalase associated with the marginal plates or with the dense bars. Immunoblot analysis of monkey kidney homogenate showed that HOX-B has a molecular mass of 42 kDa that was slightly larger than that of rat kidney HOX-B (39 kDa). The results show that the dense bar of dumb-bell-shaped peroxisomes in monkey kidney is composed of at least HOX-B and is a variation of the marginal plates.

[Coronary arteritis of Kawasaki disease unresponsive to high-dose intravenous gammaglobulin successfully treated with plasmapheresis]

Kawasaki disease (KD) is characterized by marked activation of immune system and generalized vasculitis including coronary arteritis, and the intravenous gammaglobulin therapy is recommended as the first line of the choices. However, in some fulminant cases the coronary arteritis progresses rapidly and extensively in the early phase of the disease despite of the aggressive high-dose gammaglobulin administration. Recent observations indicated that the vasculitis begins at the endothelial cells which are activated by several inflammatory cytokines and are adhered to by cytokine-activated cytotoxic immune cells. Thus, it is important for the prevention of coronary arteritis and the resultant coronary aneurysm to reduce the inflammatory cytokines in the plasma. We reported here a 4-year-old girl with coronary arteritis which began on the 3rd day of the disease. The patient was fulfilled the revised criteria of KD at the hospital admission. As the initial intravenous gammaglobulins (400 mg/kg/day for 3 consecutive days and the subsequent 1 g/kg single intravenous infusion) revealed ineffective, which was judged by echocardiography in the persistence of brightness of the slightly widened coronary artery, and by laboratory data, we conducted therapeutic approach of plasmapheresis (replacement of plasma with 5% albumin in saline) on 8-10th days of KD. Fever was down to normal range soon after the first plasmapheresis, and after the second pheresis CRP was reduced, and finally on the 10th day echocardiography demonstrated marked improvement of inflamed coronary artery. The precise mechanism of the effective plasmapheresis is to be investigated, but it is possible that the removal of inflammatory cytokines from the plasma ceased the subsequent endothelial cell damage and coronary arteritis.(ABSTRACT TRUNCATED AT 250 WORDS)

[Detection of minimal residual disease by means of FISH and PCR methods and its clinical evaluation]

The monitoring of MRD by FISH and PCR is now clinically evaluated for a prediction of the relapse of leukemia. However, these methods include several technical limitations. In FISH, an appropriate cut off value should be settled for each probe or procedure in estimating chromosomal gain, loss, or translocation and the sensitivity depends on the cut off values but it may reach to 10(-3). In PCR, the sensitivity is higher than that of FISH especially using genomic DNA as a template. However, the detection of chromosomal translocation-specific DNA or RNA constructs is currently applicable to limited cases and the amplification of Ig or TCR gene rearrangement has a major pitfall caused by the clonal evolution. Clinically, MRD can be an indicator for a prediction of the relapse. For example, a greater MRD on entering CR tends to be related with an early relapse, a return to MRD-positive after disappearance of MRD will be a sign of impending relapse, and MRD negativity at the termination of therapy may be correlated with a long-term disease free status. More precise evaluation of MRD is necessary with regard to therapeutic strategy.

Prospective monitoring of minimal residual disease during the course of chemotherapy in patients with acute lymphoblastic leukemia, and detection of contaminating tumor cells in peripheral blood stem cells for autotransplantation

A prospective study for detecting minimal residual disease (MRD) was conducted on children with acute lymphoblastic leukemia (ALL). Thirty-nine patients (38 B-lineage ALL, one T-ALL) with TCR delta rearrangements could be followed for 21 to 44 months (mean 30.9 months) excluding four patients who died. One hundred and ninety four bone marrow (BM) samples and 13 peripheral blood stem cell (PBSC) grafts were available for detection of MRD. Initially 34 cases were treated prospectively according to the CCLSG risk-stratified protocols for ALL (ALL874 or ALL911), and five cases according to the other protocols. Conventional chemotherapy was replaced by autologous PBSC transplantation (PBSCT) in five patients, by allogenic BM transplantation (BMT) in one patient, or suspended in another patient. Twenty-nine of 32 children in whom conventional chemotherapy could be continued without interruption remain in complete remission (CR). In 24 of the 29 patients MRD became undetectable within 12 months of their diagnosis. In five cases, BM samples obtained during maintenance therapy exhibited residual leukemia cells, and yet none of them relapsed (mean follow-up period 28.6 months). Our results thus indicate that intensive maintenance therapy for patients with PCR-positive results during consolidation therapy may prevent subsequent relapse. Nine events of relapse were diagnosed in eight patients (five BM, two isolated central nervous system (CNS), one combined BM and CNS, one isolated skin relapse). An increase or a re-emergence of MRD was detected in BM samples obtained from patients prior to BM relapse, but one patient remained in CR despite reappearance of leukemic cells following a PCR-negative status. Monitoring of MRD failed to predict isolated CNS or skin relapse. PBSCT allows high-dose cytoreduction therapy for patients with refractory neoplasia. In our study, leukemic cells were identified in eight of 13 PBSC grafts harvested from five patients. Three of four children who received PBSC grafts containing leukemic cells relapsed within 6 months after PBSCT. Monitoring of MRD as part of quality control of PBSC grafts may ultimately contribute to improvements in PBSCT procedures.

Neurofibromatosis 1 gene (NF1) mutation is a rare genetic event in myelodysplastic syndrome regardless of the disease progression

Neurofibromatosis 1 gene (NF1) is a tumor suppressor gene and the product of which down-regulates Nras protein by its GTPase activating protein-related domain (NF1-GRD). Although the incidence of NF1 mutation was reported to be rare in the chronic phase of myelodysplastic syndrome (MDS), there have been no previous reports on its configuration in patients showing the disease progression. We examined NF1 in 50 patients with MDS including 9 who had progressed to more advanced stages and 16 to acute leukemia. Six patients had an Nras mutation. We carried out allele specific restriction analysis (ASRA) to detect a mutation at the first nucleotide A of codon 1423 (AAG), a mutational hot spot. We also employed a polymerase chain reaction mediated single strand conformation polymorphism (PCR-SSCP) method to confirm the result of ASRA and to detect a point mutation in other sequences of FLR exon. In consequence, ASRA disclosed wild type configuration and PCR-SSCP showed no aberrant band in any sample examined whether the samples harboured an Nras mutation or not. We conclude that NF1 mutation does not play a crucial role in the development and the progression of MDS.

The distribution of cathepsin D in two types of lysosomal or endosomal profiles of rat hepatocytes as revealed by combined immunocytochemistry and acid phosphatase enzyme cytochemistry

In the electron micrographs of rat hepatocytes, acid phosphatase (ACPase)-positive profiles were classified as either round or elongate types by image analysis, according to a shape index. The former is typical of spherical lysosomes, and the latter are presumed to be the same structures that we have previously termed nematolysosomes. The localization of cathepsin D in these two types of ACPase-positive profiles was electron microscopically examined by a combination of enzyme cytochemistry for ACPase and postembedding immunocytochemistry for cathepsin D. Gold particles showing antigenic sites for cathepsin D were largely present in ACPase-positive structures, although the labeling intensity of gold particles varied with individual sectional profiles of these structures. Quantitative analysis of the labeling density in the two types of ACPase-positive profiles revealed that the amount of cathepsin D in the elongate-type population was smaller than that in the round-type one. This result suggests that the contents of most elongate ACPase-positive structures are different from those of spherical lysosomes and may be similar to those of endosomes. It was also frequently observed that some of the elongate ACPase-positive profiles labeled with few or no gold particles were fused with round profiles which were heavily labeled with gold particles for cathepsin D. It is possible that such fused profiles may be sites for junctions of the two different transport pathways for ACPase and cathepsin D being delivered to lysosomes. Finally, these elongate ACPase-positive structures seem to be equivalent to late endosomes or a different kind of lysosomes containing lower concentrations of hydrolases.