Na+/H+ exchange by brush border membrane vesicles of human ileal small intestine

Na+/H+ exchange was characterized in the ileum of human brush border membrane vesicles. We have used a well-validated technique for preparing ileal brush border membranes from human cadaveric small intestine. Sodium was transported into the intravesicular space as evident by an osmolality study, which showed negligible binding to the external surface of the vesicles. The presence of an outwardly directed pH gradient stimulated Na+ uptake compared with the no pH gradient condition. Maximal uptake occurred after 5 min with a threefold overshoot over equilibrium. The rate of Na+ uptake was dependent on the extent of the pH gradient generated across the vesicles. Amiloride at 10(-4) M concentration inhibited the initial rate of Na+ uptake by greater than 90% and prevented stimulation of Na+ uptake in the presence of an outwardly directed pH gradient. The imposition of negative membrane potential did not enhance Na+ uptake compared with voltage clamp condition under both pH gradient and no pH gradient conditions, indicating an electroneutral process. Kinetic analysis of the Na+/H+ exchanger at 5 s showed a maximum velocity of 23.2 +/- 0.3 nmol/mg protein.5 s and a Michaelis constant of 14.5 +/- 5.2 mM. These studies demonstrate the presence of a Na+/H+ exchanger in human ileal brush border membrane vesicles.     

Acute myelocytic leukemia (M0) in an elderly patient with relapsed granulocytic sarcoma (M7) of bone during the second period of complete remission 5 years after onset]

A 75-year-old man was admitted because of right knee joint pain in December 1999. He had suffered from acute myelocytic leukemia (AML: M0) in November 1994 and achieved the first complete remission (CR) then. His AML relapsed in August 1996, but fortunately he achieved a second CR. Radiographical bone examination revealed osteolytic lesions in his right knee and bone scintigraphy showed uptake in the right knee and the middle part of the left femur. MRI also revealed a low attenuation signal in the left femur. He had no abnormal findings in peripheral blood or bone marrow. Histological examination of the biopsied bone tissue showed a diffuse proliferation of round cells with medium-sized or large nuclei. These cells were histochemistrically negative for myeloperoxidase and naphtol-ASD-chloroacetate esterase, and were also negative for lysozyme, cytokeratin 7, 9, 20, EMA, CEA, CD3, CD79a on immunohistochemistry, but were positive for CD43, CD56. In immunophenotypic analysis of these cells by flow cytometry, CD7, CD13, CD33, CD41, CD56 were revealed to be strongly positive. On the basis of these findings we diagnosed these tumors as granulocytic sarcomas (GS), extramedullary recurrence of AML M7. Although radiation (36Gy) to these tumors brought a temporary relief of the pain, he died of systemic relapse of AML in February 2001. When presented CD7+ AML M0 had been diagnosed, but GS cells were also positive for CD 56 and CD41. Although CD56 had not been examined initially, he might have been had myeloid/NK cell precursor acute leukemia and CD41 might be acquired later in the course of the disease. It is known that AML M0, M7 and myeloid/NK cell precursor acute leukemia have poor prognoses, nevertheless he survived for 6 years. It may be that intensive and repeated chemotherapy for AML can obtain excellent outcome in the elderly cases in good systemic condition and with favourable prognostic factors.     

Association of Chlamydia pneumoniae antibody with the cholesterol-lowering effect of statins

To investigate the association between Chlamydia pneumoniae (C. pneumoniae) infection and atherosclerosis, we compared the effect of lipid-lowering drugs on carotid intima-media thickness (IMT) between patients who were positive and negative for C. pneumoniae antibodies. A total of 165 asymptomatic hypercholesterolemic patients were randomized to probucol (500 mg per day, n = 82) or pravastatin (10 mg per day, n = 83) and followed for 2 years. The 2-year change of IMT in the common carotid artery was the primary endpoint, while mean IMT change and major cardiovascular events were secondary endpoints. C. pneumoniae antibodies (IgA and IgG) were measured by enzyme-linked immunosorbent assay. The 50 patients without C. pneumoniae antibodies showed significant reduction of IMT progression (-19%), while no significant change of IMT was noted in the 115 antibody-positive patients (-6%). Significant inverse associations were found between the reduction of IMT progression and the C. pneumoniae IgA- and IgG-antibody index (P < 0.01 and 0.01, respectively). No significant differences in the reduction of serum total-cholesterol and LDL-cholesterol were found between antibody-positive and -negative patients. There was no significant difference of efficacy between probucol and pravastatin. These observations suggest that C. pneumoniae infection reduces the effect of lipid-lowering therapy on carotid atherosclerosis and that this organism may play a role in the progression of atherosclerosis.     

Production of a monoclonal antibody useful in the molecular characterization of murine T-cell-replacing factor/B-cell growth factor II.

T-cell-replacing factor (TRF) is a T-cell-derived factor required for terminal differentiation of activated B cells to immunoglobulin-secreting cells. Previous studies have shown that a murine T-cell hybrid (B151K12) produces factor(s) that (i) induce immunoglobulin secretion by the B-cell leukemia line BCL1 and secondary anti-2,4-dinitrophenyl IgG synthesis in vitro by dinitrophenyl-primed B cells (TRF activity) and (ii) cause proliferation of the BCL1 cells [B-cell growth factor II (BCGF-II) activity]. Both activities appear to be associated with the same molecule. Here we report the production of a monoclonal antibody to murine TRF. The monoclonal antibody, designated TB13, strongly inhibited both TRF and BCGF-II activities and absorbed TRF- as well as BCGF-II-active molecules produced by B151K12 and by Xenopus oocytes that had been injected with mRNA transcribed from plasmid pSP6K-mTRF23. Inhibition was linearly dependent on the concentration of both TB13 and TRF. Monoclonal antibody TB13 did not inhibit the activities of B-cell stimulatory factor 1, interleukin 1, interleukin 2, or interleukin 3. TRF activity in dissolved samples of immunoprecipitates obtained with TB13 was recovered after NaDodSO4/PAGE, in the fractions corresponding to a protein band at Mr 46,000. Our results indicate that monoclonal antibody TB13 recognizes a molecule that has both TRF and BCGF-II activities.     

Plasminogen activator in synovial fluid from patients with rheumatoid arthritis

The plasminogen activator in synovial fluid from patients with rheumatoid arthritis (RA) and osteoarthritis (OA) was analyzed on a molecular basis. The level of plasminogen activator in RA was found to be higher than in OA. The plaminogen activators of both RA and OA revealed 3 different molecular weights: 90,000, 55,000 and 33,000. RA demonstrated the 3 plasminogen activators in broadly comparable ratios, but OA had the 55,000 form dominantly. The 90,000 plasminogen activator was a tissue-type plasminogen activator, while the 55,000 and 33,000 plasminogen activators were of the urokinase-type. beta-Methasone suppressed the tissue-type plasminogen activator, and urinary trypsin inhibitor suppressed the urokinase-type plasminogen activators. When urinary trypsin inhibitor was injected clinically into the joint space of a patient with RA, the urokinase-type plasminogen inhibitor was suppressed as in the in vitro study, and the clinical signs and symptoms were markedly improved. Open trials of intraarticular injections of urinary trypsin inhibitor demonstrated improvement of the clinical signs and symptoms.     

Lower birth weight associated with current overweight status is related with the metabolic syndrome in obese Japanese children.

The purpose of this study was to clarify the relationship between lower birth weight and current overweight status and to examine the involvement of these factors in the development of the metabolic syndrome (MS) in obese Japanese children. We examined 97 obese boys (mean age 11.3 years; mean percentage overweight [POW] 52.4%) and 29 obese girls (mean age 11.1 years; mean POW 58.3%). The anthropometric measurements, blood pressure, fasting serum insulin and blood glucose, liver enzymes, lipids and lipoproteins were measured. Birth weight and gestational weeks were also recorded. The subjects were divided into either an MS group or a Non-MS group using criteria proposed for Japanese children. We compared the weight parameters (birth weight, current weight and current weight-to-birth weight ratio [WBWR]) between the two groups and analyzed the relationships between the weight parameters and metabolic derangements. There were no significant differences in age or anthropometric measurements between the two groups. However, birth weight in the MS group was lower than that in the Non-MS group, while WBWR of the MS group was higher than that in the Non-MS group. Blood pressure and serum insulin correlated positively with WBWR. These findings suggested that lower birth weight with current overweight status was associated with the MS in obese Japanese children. We were unable to clarify whether subjects with lower birth weight who achieved proper weight gains had the same risk as subjects with appropriate birth weight. However, they should be assisted to grow adequately to prevent future metabolic derangements.     

Serodiagnosis of hepatitis C virus (HCV) infection with an HCV core protein molecularly expressed by a recombinant baculovirus.

An enzyme-linked immunosorbent assay (ELISA) was developed for serological diagnosis of hepatitis C virus (HCV) infection, using HCV core protein (p22) synthesized by a recombinant baculovirus. Among 58 clinically well-defined chronic non-A, non-B hepatitis (NANBH) patients, 49 (84.5%) were positive for p22 antibody (anti-p22), whereas 42 (72.4%) were positive for C100-3 antibody (anti-C100-3), as measured by the present assay using the HCV nonstructural protein as antigen. Thirty-nine patients (67.2%) had both antibodies. No significant level of anti-p22 was detected in sera of chronic hepatitis B patients or normal blood donors. In typical post-transfusion NANBH patients, anti-p22 could be detected at, or even before, the first alanine aminotransferase peak. Anti-p22 was also detected in blood donors who were previously shown to be involved in transmitting HCV but in whose serum anti-C100-3 was not detectable. The ELISA detecting antibody to the HCV core protein expressed and properly processed in animal cells will be useful for mass screening of donor blood as well as for early diagnosis of hepatitis C.     

Study on pancreatic insufficiency (chronic pancreatitis) and steatorrhea in Japanese patients with low fat intake

The incidence of steatorrhea is said to be lower and its grade milder in Japanese because their fat intake is lower than that of Europeans and Americans. Failure to take this into account creates difficulties when attempting to compare data on pancreatic exocrine insufficiency in different countries. The authors examined the incidence and grade of steatorrhea in Japanese chronic pancreatitis (CP) patients whose daily fat intake was <40 g (25 patients) or > or =40 g (35 patients). In addition, 23 CP patients with steatorrhea and daily fecal fat excretion > or =5 g were given a pancreatic enzyme preparation at a dose 3-8 times higher than the usual dose to investigate its effect on fecal fat excretion. Among CP patients whose fat intake was <40 g, the incidence of fecal fat excretion <5 g was 56% and that of fecal fat excretion > or =10 g (severe steatorrhea) was 8%. In CP patients whose fat intake was > or =40 g, the incidences were 27.9 and 34.9%, respectively; a significant increase in the number of affected patients was noted when fat intake was > or =40 g. The fat absorption rate was 76.2% among patients whose fat intake was <40 g and 77.8% among patients whose fat intake was > or =40 g, revealing no significant difference between the two groups. The proportion of CP patients whose fat absorption rate < or =80% was 32% at a fat intake <40 g and 39% at a fat intake > or =40 g, revealing no significant difference between the two groups.