mDia1/3-dependent actin polymerization spatiotemporally controls LAT phosphorylation by Zap70 at the immune synapse

The mechanism by which the cytosolic protein Zap70 physically interacts with and phosphorylates its substrate, the transmembrane protein LAT, upon T cell receptor (TCR) stimulation remains largely obscure. In this study, we found that the pharmacological inhibition of formins, a major class of actin nucleators, suppressed LAT phosphorylation by Zap70, despite TCR stimulation-dependent phosphorylation of Zap70 remaining intact. High-resolution imaging and three-dimensional image reconstruction revealed that localization of phosphorylated Zap70 to the immune synapse (IS) and subsequent LAT phosphorylation are critically dependent on formin-mediated actin polymerization. Using knockout mice, we identify mDia1 and mDia3, which are highly expressed in T cells and which localize to the IS upon TCR activation, as the critical formins mediating this process. Our findings therefore describe previously unsuspected roles for mDia1 and mDia3 in the spatiotemporal control of Zap70-dependent LAT phosphorylation at the IS through regulation of filamentous actin, and underscore their physiological importance in TCR signaling.

Strong coupling superconductivity at 8.4 K in an antiperovskite phosphide SrPt3P

We report the discovery of a family of ternary platinum phosphides APt3P (A = Ca, Sr, and La), which crystallize in an antiperovskite-based structure closely related to that of the heavy fermion superconductor CePt3Si. All three phosphides showed superconductivity at low temperatures and the highest critical temperature T(c) = 8.4  K was observed for SrPt3P. The analysis of specific heat C(T) for SrPt3P shows clear evidence for very strong coupling s-wave superconductivity with a large ratio between superconducting gap Δ0 and T(c), 2Δ0/k(B)T(c) ∼ 5, and the presence of low-energy phonons. The presence of multiple Fermi surface pockets was inferred from the nonlinear magnetic field dependence of Hall resistivity, which we argue might play a role in realizing the strong coupling of charge carriers with the low-lying phonons.

Two distinct steps of immigration of hematopoietic progenitors into the early thymus anlage

Thymic epithelial cells, which create a three-dimensionally organized meshwork structure peculiar to the thymus, develop from simple epithelia of the third pharyngeal pouch and cleft during organogenesis. We comparatively investigated the thymus anlages of normal and nude mice by immunohistochemical analysis with regard to epithelial organization and distribution of hematopoietic progenitor cells at early stages of organogenesis. Our results show that development of the mouse thymus anlage at early stages can be subdivided into at least two stages by the differences in epithelial organization, i.e. stratified epithelial stage on embryonic day (Ed) 11 and clustered epithelial stage on Ed12. At the former stage, hematopoietic progenitor cells are accumulated in the mesenchymal layer of the thymus anlage, and at the latter stage progenitor cells enter the epithelial cluster and proliferate. In nude mice, hematopoietic progenitor cells are found in the mesenchymal layer on Ed11.5, but they are not observed among epithelial cells on Ed12, even though epithelial cells form a cluster structure. The present results suggest that aberrant development of the nude mouse thymus anlage occurs at the clustered epithelial stage and that epithelial cells of the nude anlage lack the ability to induce the entrance of hematopoietic progenitor cells into the epithelial cluster.

Expression of alpha(4)beta(7) integrin defines a distinct pathway of lymphoid progenitors committed to T cells, fetal intestinal lymphotoxin producer, NK, and dendritic cells

During embryogenesis, the Peyer's patch anlagen are induced by a cell population that produces lymphotoxin (LT) alpha(1)beta(2) following stimulation of IL-7Ralpha. In this study, we show that the LT-producing cell is localized within the IL-7Ralpha(+) and integrin alpha(4)beta(7) (alpha(4)beta(7))(+) population in the embryonic intestine. Lineage commitment to the LT producer phenotype in the fetal liver coincides with expression of alpha(4)beta(7). Before expression of alpha(4)beta(7), the potential of IL-7Ralpha(+) population to generate B cells is lost. However, the progenitors for T cells and LT producer cells reside in the IL-7Ralpha(+)alpha(4)beta(7)(+) cells, but during subsequent differentiation, the potential to give rise to T cells is lost. This IL-7Ralpha(+)alpha(4)beta(7)(+) population migrates to the intestine, where it induces the Peyer's patch anlagen. When stimulated with IL-15 or IL-3 and TNF, the intestinal IL-7Ralpha(+)alpha(4)beta(7)(+) population can differentiate into fully competent NK1.1(+) NK cells or CD11c(+) APCs. Expression of alpha(4)beta(7) is lost during differentiation of both lineages; IL-7Ralpha expression is lost during NK1.1(+) cells differentiation. A newly discovered lineage(-)IL-7Ralpha(+)c-Kit(+)alpha(4)beta(7)(+) population in the fetal liver is committed to T, NK, dendritic, and fetal intestinal LT producer lineage, the latter being an intermediate stage during differentiation of NK and dendritic cells.

The earliest stages of B cell development require a chemokine stromal cell-derived factor/pre-B cell growth-stimulating factor

Environmental factors essential for the first stages of B lymphopoiesis remain elusive. Here, we report that immediately after commitment to B lineage, precursors become dependent on a chemokine SDF-1 and its receptor CXCR4 using mutant and radiation chimeric mice. In bone marrow, generation of the earliest identifiable B cell precursor populations requires CXCR4. In fetal liver, we identified Lin(-)CD19(-)c-kit(+)IL-7Ralpha(+)AA4.1(+), the earliest unipotent B cell precursor population, and found that its development was severely affected in SDF-1(-/-) embryos but not in IL-7(-/-) embryos. Lin(-) T cell progenitors appeared normal in SDF-1(-/-) embryos. Moreover, SDF-1 exhibited specific biologic activities on the earliest B cell precursors. SDF-1 provides the first example of a cytokine responsible for the earliest B lineage stages.

Effects of sensory feedback on variations on intertap interval and force in finger-tapping sequences

This study was designed to examine effects of somatosensory feedback on variations of intertap interval and muscle force in finger-tapping sequences over 10 minutes. Although intertap intervals were decreased on the massed task as the time passed, the intervals were constant in the distributed task. In finger-tapping for a long time, impulses perhaps circulate within the loop circuits between the cerebral motor cortex and the peripheral nerve and subsequently increase further the excitability of the circuits. This increase in the excitability within the circuits may shorten the interval and increase variation of the interval. On the other hand, although peak force increased up to the 5-min. mark on the massed task, the force decreased after the 6-min. mark. This increase of force also may be produced by increasing activation of the corticoperipheral loop circuits. Although the decrease of force was perhaps produced by the fatigue of finger muscles for tapping during a few minutes, fatigue appeared more clearly in muscle force than in timing control. However, the force and the variation were constant in the distributed task.

Basic fibroblast growth factor up-regulates the surface expression of complement receptors on human monocytes

OBJECTIVE AND DESIGN

To clarify the possible involvement of basic fibroblast growth factor (b-FGF) in inflammation, we examined the effect of b-FGF on the surface expression of complement receptors (CR) on human monocytes in vitro.

MATERIALS AND METHODS

Heparinized venous blood was obtained from healthy adult donors. The surface expression of CR on blood monocytes was determined by two-color immunofluorescent staining using flow cytometry and monoclonal antibodies. A standard whole blood lysis technique was used to avoid any in vitro manipulation that would activate monocytes.

RESULTS

b-FGF increased the expression of CR3 on monocytes in a dose- and time-dependent manner. The b-FGF concentrations used were up to 100 ng/ml. The values of mean fluorescence intensity (MFI) of CR3 expression on unstimulated monocytes were 12.6+/-1.3 (n = 3), whereas those on b-FGF-stimulated monocytes were 59.2+/-7.1 (n = 3). b-FGF also up-regulated the expression of CR1 on monocytes in a dose- and time-dependent manner. The MFI values of CR1 expression on unstimulated monocytes were 2.5+/-0.1 (n = 3), whereas those on b-FGF-stimulated monocytes were 11.1+/-0.6 (n=3). The magnitude of CR1 expression by monocytes was significantly smaller than that of CR3 expression. The maximal stimulatory effect of b-FGF on monocytes was observed using greater than 25 ng/ml of b-FGF and 90-120 min incubation period.

CONCLUSION

b-FGF may participate in the inflammatory process by modulating the CR expression on blood monocytes.

Commitment to natural killer cells requires the helix-loop-helix inhibitor Id2

We have previously described how T and natural killer (NK) lineage commitment proceeds from common T/NK progenitors (p-T/NK) in the murine fetal thymus (FT), with the use of a clonal assay system capable of discriminating p-T/NK from unipotent T or NK lineage-committed progenitors (p-T and p-NK, respectively). The molecular mechanisms controlling the commitment processes, however, are yet to be defined. In this study, we investigated the progenitor activity of FT cells from Id2-/- mice that exhibit defective NK cell development. In the Id2-/- FT, NK cells were greatly reduced, and a cell population that exclusively contains p-NK in the wild-type thymus was completely missing. Id2-/- FT progenitors were unable to differentiate into NK cells in IL-2-supplemented-FT organ culture. Single progenitor analysis demonstrated that all Id2-/- fetal thymic progenitors are destined for the T cell lineage, whereas progenitors for T/NK, T, and NK cell lineages were found in the control. Interestingly, the total progenitor number was similar between Id2-/- and Id2+/+ embryos analyzed. Expression of Id2 was correlated with p-NK activity. Our results suggest that Id2 is indispensable in thymic NK cell development, where it most probably restricts bipotent T/NK progenitors to the NK cell lineage.

Immature multipotent hemopoietic progenitors lacking long-term bone marrow-reconstituting activity in the aorta-gonad-mesonephros region of murine day 10 fetuses

Previous studies indicated that multipotent progenitors exist in early fetuses that do not contain long-term reconstituting (LTR) activity. However, it remained unclear whether these multipotent progenitors are committed to the hemopoietic lineage or are immature mesodermal cells or hemangioblasts. In this study, we have succeeded in enriching the multipotent progenitors that are capable of generating myeloid, T, and B cells in the LFA-1(-) subpopulation of TER-119(-)c-kit(+)CD45(+) cells from the aorta-gonad-mesonephros (AGM) region of day 10 fetuses. We found that these day 10 AGM LFA-1(-) cells do not show the LTR activity, whereas day 11 AGM LFA-1(-) cells do have such an activity. These results strongly suggest that multipotent progenitors lacking LTR activity emerge as CD45(+) hemopoietic progenitor cells in the AGM region on the 10th day of gestation, and such p-Multi mature into hemopoietic stem cells by acquiring LTR activity.

Retention of relative force in the scaling of a serial force pattern with an attenuated-force tap

The present study was designed to examine the retention of relative force in the scaling of a serial force pattern in a finger-tapping sequence using an attenuated tap. On practice trials, 12 undergraduate students tapped a force plate connected to strain gauges that gave them feedback about the force. On test trials, participants recalled the force pattern (200 gm-200 gm-200 gm-100 gm) and the intertap interval (400 msec.) practiced during the practice period without the feedback (recalled task). Then, they adaptively produced a halved (halved task) or doubled force profile (doubled task) at the fixed intertap interval. Analyses showed that mean peak forces at the first three tap positions of the tapping sequence undershot the expected forces across all tasks. Hence, the ratios of the forces in Serial Positions 1:4, 2:4, and 3:4 were considerably lower than 2.0. This is a contextual effect suggesting that the last attenuated tap affected the first three taps of the tapping sequence. Thus, because the relative force of movements appears to be a weaker invariant feature than sequencing and relative timing for generalized motor program theory of Schmidt and Lee, this finding does not support the relative force for a generalized motor program.

Stepwise lineage restriction of progenitors in lympho-myelopoiesis

It has long been controversial whether hematopoiesis progresses through ordered stages of determination as in embryonic development. This is due to the absence of a methodology capable of exactly determining the developmental potential of hematopoietic stem/progenitor cells. The multilineage progenitor (MLP) assay enabled us to discriminate among seven types of hematopoietic progenitors, which are multipotent progenitor p-MTB (capable of generating myeloid, T and B cells), bipotent progenitors p-MT, p-MB and p-TB, and unipotent progenitors p-M, p-T and p-B. Among these seven types, the p-TB type progenitor was found to be absent. These findings indicate that the process of lineage commitment proceeds through an ordered but not random process. By extending the area of investigation to include the erythroid lineage, more convincing evidence for the ordered process was obtained. Detailed and exact illustration of the process of hematopoiesis will provide an opportunity to revive hematopoiesis as one of the most fascinating targets of research in developmental biology.

Progression of T cell lineage restriction in the earliest subpopulation of murine adult thymus visualized by the expression of lck proximal promoter activity

The proximal promoter of lck directs gene expression exclusively in T cells. To investigate the developmental regulation of the lck proximal promoter activity and its relationship to T cell lineage commitment, a green fluorescence protein (GFP) transgenic (Tg) mouse in which the GFP expression is under the control of the proximal promoter of lck was created. In the adult GFP-Tg mice, >90% of CD4(+)CD8(+) and CD4(+)CD8(-) thymocytes, and the majority of CD4(-)CD8(+) and CD4(-)CD8(-) [double-negative (DN)] thymocytes were highly positive for GFP. Slightly lower but substantial levels of expression of GFP was also observed in mature splenic T cells. No GFP(+) cells was detected in non-T lineage subsets, including mature and immature B cells, CD5(+) B cells, and NK cells, indicating a preserved tissue specificity of the promoter. The earliest GFP(+) cells detected were found in the CD44(+)CD25(-) DN thymocyte subpopulation. The developmental potential of GFP(-) and GFP(+) cells in the CD44(+)CD25(-) DN fraction was examined using in vitro culture systems. The generation of substantial numbers of alphabeta and gammadelta T cells as well as NK cells was demonstrated from both GFP(-) and GFP(+) cells. However, no development of B cells or dendritic cells was detected from GFP(+) CD44(+)CD25(-) DN thymocytes. These results suggest that the progenitors expressing lck proximal promoter activity in the CD44(+)CD25(-) DN thymocyte subset have lost most of the progenitor potential for the B and dendritic cell lineage. Thus, progression of T cell lineage restriction in the earliest thymic population can be visualized by lck proximal promoter activity, suggesting a potential role of Lck in the T cell lineage commitment.

Retention and adaptive control of force pattern on a finger-tapping sequence with an attenuated force tap

The present study was designed to examine the retention and adaptive control of a force pattern in the scaling of speed profiles in a finger-tapping sequence with an attenuated tap. On practice trials, 11 college students tapped on a force plate connected to strain gauges with feedback. On test trials, participants recalled the force pattern (200 gm-200 gm-200 gm-100 gm) and the intertap interval 1400 msec.) acquired during practice without feedback (recalled task). Then, participants adaptively tapped the acquired force pattern at the half (speeded task) and double (slowed task) the intertap interval acquired during the practice. Analyses showed that mean peak forces increased across tasks as the tapping speed was slowed down. Mean peak forces at the first three tap positions in sequence were smaller than the required forces in both the recall and speeded tasks. So, although the slowed task had the lowest ratio of forces in serial positions 1:4, 2:4, and 3:4, the ratios were less than 2 across tasks. These indicated that changing to a slow pace creates a more difficult adaptive task than changing to a fast pace, and further that a serial force pattern with an attenuated force creates a more difficult motor task for fine control than that with an accentuated force.

Basic fibroblast growth factor modulates the surface expression of effector cell molecules and primes respiratory burst activity in human neutrophils

Basic fibroblast growth factor (b-FGF) mediates a variety of biological responses such as angiogenesis and hematopoiesis. We examined the effect of b-FGF on human neutrophil functions in vitro. The surface expression of effector cell molecules on neutrophils was determined by flow cytometry and monoclonal antibodies. b-FGF increased the expression of CD11b leukocyte integrin and complement receptor type 1 on neutrophils and decreased the expression of L-selectin on neutrophils in a dose- and time-dependent manner. We also examined the effect of b-FGF on the respiratory burst activity in neutrophils. Although b-FGF alone did not induce intracellular oxidative product formation by neutrophils, it enhanced H(2)O(2) production in neutrophils stimulated by N-formyl-methionyl-leucyl-phenylalanine or phorbol myristate acetate. These findings suggest that b-FGF may participate in the inflammatory process via modulating the surface expression of effector cell molecules and enhancing respiratory burst activity in neutrophils.

Anti-Helicobacter pylori agents. 4. 2-(Substituted guanidino)-4-phenylthiazoles and some structurally rigid derivatives

In order to find a new class of anti-Helicobacter pylori (H. pylori) agents, a series of 4-[(3-acetamido)phenyl]-2-(substituted guanidino)thiazoles and some structurally rigid analoges were synthesized and evaluated for antimicrobial activity against H. pylori. Among the compounds obtained, high anti-H. pyrori activities were observed in benzyl derivative 34 (MIC = 0.025 microg/mL) and phenethyl derivatives 35 and 36 (MIC = 0.037 microg/mL and 0.017 microg/mL). Though alkyl derivatives generally showed lower activity, the 2-methoxyethyl derivative 28 preserved significant activity (MIC = 0.32 microg/mL) and also exhibited more potent gastric antisecretory activity than ranitidine. Structural restriction by bridging between the thiazole and the phenyl rings with an alkyl chain did not improve the activity in this series.

The monoclonal antibody TER-119 recognizes a molecule associated with glycophorin A and specifically marks the late stages of murine erythroid lineage

The antigen specificity of a rat monoclonal antibody TER-119 was investigated. In adult mice, TER-119 reacted with mature erythrocytes, 20-25% of bone marrow cells and 2-3% of spleen cells but not with thymocytes nor lymph node cells. In fetal haematopoietic tissues, 30-40% of d 10 yolk sac cells, 80-90% of d 14 fetal liver cells and 40-50% of newborn liver cells were reactive with TER-119. TER-119+ cells in adult bone marrow expressed significant levels of CD45 but not myeloid (Mac-1, Gr-1) or B-cell (B220) markers. Morphological examination and haematopoietic colony-forming assays for isolated TER-119+ cells revealed that TER-119 reacts with erythroid cells at differentiation stages from early proerythroblast to mature erythrocyte, but not with cells showing typical erythroid blast-forming unit (BFU-E) and erythroid colony-forming unit (CFU-E) activities. Erythroleukaemia cell lines do not express the TER-119 antigen even after stimulation with dimethylsulphoxide. TER-119 immunoprecipitated protein bands with molecular masses of 110 kDa, 60 kDa, 52 kDa and 32 kDa from erythrocyte membrane, whereas only a 52-kDa band was detected by TER-119 in Western blot analysis. Further molecular and cellular analyses indicated that the TER-119 antigen is a molecule associated with cell-surface glycophorin A but not with glycophorin A itself.

T cell progenitors emerge earlier than B cell progenitors in the murine fetal liver

The developmental potential of individual cells in the Lin-c-kit+CD45+IL-7R+ (IL-7R+) population from murine fetal liver was investigated using a clonal assay capable of determining the potential of a progenitor to give rise to myeloid, T, and B cells. Unipotent progenitors generating T cells (p-T) or B cells (p-B) but not other types of progenitors were found in the IL-7R+ population. A large proportion of progenitors at day 12 of gestation are p-T, whereas the frequency of p-T dramatically decreases with gestational age. In marked contrast, p-B are very rare by day 12, but they rapidly increase thereafter. These findings strongly suggest that the commitment of multipotent progenitors to T and B cell lineages occurs independently.

Multivariate analysis of prognostic determinants after surgery for renal cell carcinoma at Himeji National Hospital

A clinico-pathological study was performed retrospectively on 62 patients who underwent surgery for renal cell carcinoma between January 1992 and October 1998 at Himeji National Hospital to clarify the prognostic determinants for survival. The median follow-up period was 32 months and the cause-specific survival rates at 1, 3 and 5 years were 86.7, 81.3, 81.3%, respectively. Of the 62 patients, 11 (17.7%) patients died of renal cell carcinoma and 2 (3.2%) patients died of unrelated causes. Of the variables related to survival, presenting symptoms, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), alkaline phosphatase (ALP), tumor size, pathological tumor grade, infiltration pattern, pathological tumor stage, N classification and M classification were significant risk factors for survival by univariate analysis. However, ALP, N classification and M classification were significant for survival as determined by the step-wise procedure and M classification was the most significant factor according to Cox's proportional hazard model analysis.

Type 1 diabetes mellitus caused by treatment with interferon-beta

A 57-year-old man was referred to our outpatient clinic after interferon-beta (IFN-beta) treatment for 7 weeks. While IFN-beta therapy was continued in our outpatient clinic, his blood glucose level increased gradually, and he was admitted to our hospital for hyperglycemia. The patient was prescribed a 1,600-kcal diet and intensive insulin therapy was performed. GAD antibody became positive 15 months after the start of IFN therapy, and disappeared 27 months after the start of IFN therapy. Insulin secretion was depleted and the patient had HLA-DR4, B54, and DRB1*0405. This appears to be a case of type 1 diabetes mellitus induced by administration of IFN-beta alone.

Emergence of T, B, and myeloid lineage-committed as well as multipotent hemopoietic progenitors in the aorta-gonad-mesonephros region of day 10 fetuses of the mouse

We investigated the developmental potential of hemopoietic progenitors in the aorta-gonad-mesonephros (AGM) region, where the definitive type hemopoietic progenitors have been shown to emerge before the fetal liver develops. By using an assay system that is able to determine the developmental potential of individual progenitors toward the T, B, and myeloid lineages, we show that not only multipotent progenitors but also progenitors committed to the T, B, or myeloid lineage already exist in this region of day 10 fetuses. Bipotent progenitors generating myeloid and T cells or those generating myeloid and B cells were also detected, suggesting that the commitment to T and B cell lineages is in progress in the AGM region. The numbers of these progenitors, however, were only 1/200-1/1000 of those in fetal liver of day 12 fetuses. Such small numbers of progenitors suggest that hemopoiesis has just started in the AGM region of day 10 fetuses. Although most of T cell lineage-committed progenitors in the AGM region generated only a small number of immature T cells, some were able to generate a large number of mature T cells. The detection of various types of lineage-committed progenitors strongly suggests that the AGM region is not only the site of stem cell emergence, but also the site of hemopoiesis, including lineage commitment. The T cell progenitors found in the AGM region may represent the first immigrants to the thymus anlage.

FR145715, a novel histamine H2 receptor antagonist, with specific anti-Helicobacter pylori activities

The pharmacological profile of N-[3-[2-[N'-(2-methoxyethyl)guanidino]thiazol-4yl]benzyl-ace tamide (FR145715), a novel histamine H2 receptor antagonist, was examined in both in vitro and in vivo models using experimental animals in comparison with ranitidine. In isolated guinea-pig atria, FR145715 antagonized the effect of histamine on heart rate with approximately three times more potent activity than ranitidine. In in vivo experiments, intraduodenal FR145715 dose-dependently inhibited spontaneous gastric acid secretion in rats (Shay's rats), with a ED50 value of 18.4 mg/kg, which was comparable to that of ranitidine (30.5 mg/kg). FR145715 also inhibited histamine-stimulated acid secretion in stomach-perfused anaesthetized rats (Schild's rats), when given intravenously and intraduodenally with ED50 values of 0.59 and 2.72 mg/kg, respectively. Ranitidine displayed more potent activity having respective ED50 values of 0.10 and 0.17 mg/kg. In Heidenhain pouch dogs, intravenous and oral FR145715 dose-dependently inhibited gastrin-stimulated acid secretion with respective ED50 values of 0.12 and 0.32 mg/kg, which were similar to those of ranitidine (0.09 and 0.33 mg/kg). In gastric ulcer models, FR145715 dose-dependently inhibited water immersion restraint stress- and acidified aspirin-induced gastric lesions with ED50 values of 3.2 and 15.1 mg/kg (p.o.), respectively. The comparative compound, ranitidine, also showed beneficial effects on stress-induced gastric ulcers with an ED50 value of 1.5 mg/kg (p.o.). However, it failed to inhibit acidified aspirin-induced gastric ulcers. FR145715 inhibited HCl-induced gastric lesions in rats, while pre-treatment with indomethacin abolished its beneficial effects, suggesting that FR145715 has a so-called cytoprotective effect which is dependent on endogenous prostaglandin production. In addition to its atypical profile as a histamine H2 receptor antagonist, FR145715 exhibited strong anti-microbial activities against strains of Helicobacter pylori (H. pylori) with a mean minimal inhibitory concentration value of 0.32 microg/ml. Moreover, FR145715 showed no anti-microbial effects on 25 other bacteria examined. In addition, in vivo experiments using gnotobiotic piglets infected with H. pylori, FR145715 (16 mg/kg, t.i.d.) completely eliminated the organism with reduced intensity of inflammation, when treated orally for 10 days. These data demonstrate that FR145715 is a novel histamine H2 receptor antagonist having potent and selective anti-H. pylori activities as well as cytoprotective properties. The present data suggest that FR145715 might be useful for the patients suffering from ulcer relapse, since the drug might be able to eradicate H. pylori in the stomach, which is considered a key factor to cause ulcer recurrence in humans.

Anti-Helicobacter pylori agents. 3. 2-[(Arylalkyl)guanidino]-4-furylthiazoles

A series of 2-[(arylalkyl)guanidino]-4-[(5-acetamidomethyl)furan-2-yl]thiazole s and some 4-acetamidomethyl positional isomers were synthesized and evaluated for antimicrobial activity against Helicobacter pylori. Among the compounds that had potent antimicrobial activity (MIC < 0. 1 microgram/mL), compounds 31 and 36 additionally possessed H2 antagonist and gastric antisecretory activities. Though compound 51, an analogue incorporating a methyl group onto the furan nucleus of 36, and compound 54, a positional isomer of 51, also showed potent anti-H. pylori activity, the H2 antagonism profile was eliminated from these compounds. Thus, two types of potent anti-H. pylori agents could be derived from the same scaffold.

ProMMP-9 (92 kDa gelatinase) in vitreous fluid of patients with proliferative diabetic retinopathy

Matrix metalloproteinases (MMPs) are implicated in tissue destruction during various pathophysiologic conditions. The vitreous body is a gel-like extracellular matrix that undergoes liquefaction during aging and pathological processes. To investigate the pathogenic role of MMPs in proliferative diabetic retinopathy (PDR), we studied 73 eyes from PDR patients and 25 eyes from patients with non-diabetic ocular diseases. Vitreous MMPs were measured by zymography. Retinopathy was assessed by ophthalmoscopy and PDR was classified into 3 stages, 'naked', 'active', and 'quiescent'. Although proMMP-9 was expressed in only 8% (2/25) of non-diabetic patients, it was expressed in more than 80% (38/47) of 'active' PDR patients and still expressed in 60% (9/15) of those with 'quiescent' PDR. Vascular endothelial growth factor (VEGF) in vitreous fluids was undetectable (<0.16 ng/ml) in most of the non-diabetic patients, and was maximally elevated in the 'active' PDR patients (mean=2.20 ng/ml, range; 0.16-7.61), declining in patients with 'quiescent' PDR (1.04 ng/ml, 0.16-3.77). These results suggest that MMP-9 is one of the noteworthy factors in relation to the progress of PDR, as well as angiogenic cytokines such as VEGF.

Transmission electron microscopic study of interface between bioactive bone cement and bone: comparison of apatite and wollastonite containing glass-ceramic filler with hydroxyapatite and beta-tricalcium phosphate fillers

We developed a bioactive bone cement that consists of apatite and wollastonite containing glass-ceramic (AW-GC) powder and bisphenol-a-glycidyl methacrylate (Bis-GMA) based resin. In this study, we made three types of cement (designated AWC, HAC, and TCPC) consisting of either AW-GC, hydroxyapatite (HA), or beta-tricalcium phosphate (beta-TCP) powder as the inorganic filler and Bis-GMA based resin as the organic matrix. These cements were implanted into rat tibiae and cured in situ. Specimens were prepared 1, 2, 4, and 8 weeks after the operation and observed using transmission electron microscopy. Each of the bone cements was in direct contact with the bone. In AWC-implanted tibiae, the uncured surface layer of Bis-GMA based resin was completely filled with newly formed bone-like tissue 2 weeks after implantation. The AW-GC particles were surrounded by bone and were in contact with bone through an apatite layer. No intervening soft tissue was seen. In HAC-implanted tibiae, it took 4 weeks for the uncured layer to completely fill with newly formed bonelike tissue. The HA particles were also in contact with bone through an apatite layer. In TCPC-implanted tibiae, it took 8 weeks for the uncured layer to fill with newly formed bone-like tissue. The new bone that formed on the TCPC was not as dense as that on the AWC or HAC, and an intervening apatite layer was not evident. Results indicated that AWC had higher bioactivity than either HAC or TCPC.

Endorectal ultrasonography for the assessment of rectal wall invasion in intrapelvic tumor: a preliminary report

BACKGROUND

The purpose of the present study was to determine the usefulness of endorectal ultrasonography (ERUS) in assessing rectal wall involvement in intrapelvic tumors.

METHODS

Rectal wall invasion was assessed in 16 patients; 14 with deeply invasive bladder tumors, one with prostatic leiomyosarcoma, and one with prostatic leiomyoma. Computed tomography (CT), magnetic resonance (MR) imaging and ERUS with a flexible-type radial scanner (7.5 MHz) were used and the results were compared with the histopathologic findings in surgical specimens.

RESULTS

The normal rectum was shown by ERUS to be a five- or seven-layer structure. Characteristic abnormal ERUS findings included disappearance of the perirectal fat tissue layer with or without disruption of the propria muscle layer. Endorectal ultrasonography accurately assessed rectal wall involvement in all four patients who had two bladder tumors, plus the one patient with prostatic leiomyoma and the one with prostatic leiomyosarcoma. However, ERUS overstaged one of 12 bladder tumors with no rectal wall involvement, which was strongly adhesive to the rectum because of an inflammatory change but had no tumor invasion. There were no cases of understaging by ERUS. In comparison, CT accurately assessed rectal wall involvement in two patients, but overstaged in three and understaged in two. Magnetic resonance imaging, which was performed in 14 patients, accurately assessed rectal wall involvement in two patients, but overstaged in three and understaged in one.

CONCLUSION

This preliminary study suggests that ERUS more accurately assesses rectal wall involvement in intrapelvic tumor than CT or MRI.

A cell-autonomous requirement for CXCR4 in long-term lymphoid and myeloid reconstitution

Mice lacking the chemokine stromal cell-derived factor/pre-B cell growth stimulating factor or its primary physiological receptor CXCR4 revealed defects in B lymphopoiesis and bone marrow myelopoiesis during embryogenesis. We show here that adoptive transfer experiments reveal a deficiency in long-term lymphoid and myeloid repopulation in adult bone marrow by CXCR4-/- fetal liver cells, although stromal cell-derived factor/pre-B cell growth stimulating factor-/- fetal liver cells yield normal multilineage reconstitution. These findings indicate that CXCR4 is required cell autonomously for lymphoid and myeloid repopulation in bone marrow. In addition, CXCR4-/- fetal liver cells generated much more severely reduced numbers of B cells relative to other lineages in bone marrow. Furthermore, the repopulation of c-kit+ Sca-1(+) linlow/- cells by CXCR4-/- fetal liver cells was less affected compared with c-kit+ Sca-1(-) linlow/- cells. By previous studies, it has been shown that c-kit+ Sca-1(+) linlow/- cells are highly purified primitive hematopoietic progenitors and that c-kit+ Sca-1(-) linlow/- cells are more committed hematopoietic progenitors in mice. Thus, CXCR4 may play an essential role in generation and/or expansion of early hematopoietic progenitors within bone marrow.

Emergence of T cell progenitors without B cell or myeloid differentiation potential at the earliest stage of hematopoiesis in the murine fetal liver

It has been unclear whether the progenitors colonizing the thymus are multipotent or T cell lineage restricted. We investigated the developmental potential of hematopoietic progenitors in various populations of liver and blood cells from day 12 fetuses using the recently established in vitro experimental system effective in determining the capability of individual progenitors to generate T, B, and myeloid cells. Multipotent progenitors (p-Multi) were exclusively found in the Sca-1 high-positive (Sca-1high) subpopulation of lineage marker (Lin)-c-kit+CD45+ fetal liver cells. Restriction of developmental capacity begins at the Sca-1high stage, and a large majority of progenitors in the Sca-1low or Sca-1- population are restricted to generate T, B, or myeloid cells. Such a lineage commitment or restriction taking place in the fetal liver is independent of the thymus, because no difference in the proportion of different types of progenitors were seen between nu/nu and nu/+ fetuses. T cell lineage-restricted progenitors (p-T) were abundant in the blood of day 12 fetuses, whereas p-Multi were undetectable. It was further shown that the p-Multi generated a large number of B and myeloid cells in the thymic lobe. These results strongly suggest that it is p-T but not p-Multi that migrate into the thymus.

Quantitative histochemical study of hyaluronic acid binding protein and the activity of uridine diphosphoglucose dehydrogenase in the synovium of patients with rheumatoid arthritis

OBJECTIVE

To examine hyaluronic acid (HA) dynamics in synovia with rheumatoid arthritis (RA), relying on a new quantitative technique introduced into histochemistry.

STUDY DESIGN

Synovial lesions from 28 patients were classified into four histologic stages of RA according to the degree of inflammation. The distribution of HA was histochemically investigated with a hyaluronic acid binding protein (HABP) and that of HA-producing cells enzyme histochemically with the expression of uridine diphosphoglucose dehydrogenase (UDPGD) activity in the synovium of RA patients. The results were quantified using an image processor for analytical pathology. The positive area of HABP reaction, the number of UDPGD-positive cells and the color density of the enzyme-histochemistry of UDPGD activity were measured with the IPAP system.

RESULTS

HA was shown to be diffusely distributed in the synovia, particularly densely in the superficial layer, and the distribution overlapped with that of UDPGD activation. HA distribution and UDPGD activity varied with the severity of synovial inflammation, and the positive area was the most extensive in the early stage, while it completely disappeared in the fibrotic stage.

CONCLUSION

We assume that for HA, not only does the production decrease, but the range of distribution contracts with time.

Thymic microenvironments, 3-D versus 2-D?

Lympho-stromal interactions in the thymus crucially de- termine the fate of developing T cells. Epithelial cells, inter- digitating reticular cells, macrophages and fibroblasts all play a role in the shaping of the T cell repertoire. Recently published evidence shows that lympho-stromal interaction acts bi-directional. Developing T cell themselves, at different stages of differentiation, control the microarchitecture of thymic microenvironments, a phenomenon designated as 'crosstalk'. This paper reviews experiments showing that developing T cells crosstalk to different thymic epithelial cells in a stepwise fashion. In this way, correctly organized thymic microenvironments guarantee normal thymopoiesis.

Clinical significance of increased mobility in the sagittal plane in patients with hallux valgus

Hallux valgus (HV) deformity is not always accompanied by pain. We compared roentgenograms of 32 feet of people with HV deformity and pain to roentgenograms of 22 feet of people with painless HV deformity. Twenty-three feet without HV deformity or pain were used as controls. Weightbearing and nonweightbearing roentgenograms of the lateral talar-first metatarsal angle showed a statistically significant difference between feet with deformity and pain compared with feet with painless HV, or compared with normal feet. Changes in the angles of HV between weightbearing and nonweight-bearing situations showed significant differences between HV feet and normal feet, whether or not they had pain. In HV patients, increased mobility in the sagittal plane may play a considerable role in the development of pain.

Enhancement of activation-induced cell death by fibronectin in murine CD4+ CD8+ thymocytes

Development of T cells in the thymus is achieved through the interactions of thymocytes with their microenvironments. This study focused on the function of fibronectin (FN), a major extracellular matrix molecule in the thymus, in the cell death induced by activation via the T-cell antigen receptor. FN alone did not increase cell death in murine thymocytes above the baseline level, but it significantly enhanced the cell death induced by fixed anti-CD3 monoclonal antibody (mAb), especially when a high concentration of anti-CD3 mAb was used. DNA fragmentation increased in parallel with cell death, indicating that cell death was a result of the apoptosis. Fluorescence-activated cell sorter (FACS) analysis revealed that the activation-induced cell death (AICD) caused by anti-CD3 mAb alone, or by a combination of anti-CD3 mAb and FN, occurred selectively in CD4+ CD8+ thymocytes. Very late activation antigen (VLA)-4 and VLA-5 are two major ligands to FN on thymocytes. The expression of both ligands was investigated at different stages of thymocyte development. VLA-4 was predominantly expressed at the CD4- CD8- stage, and thereafter the expression was reduced, whereas VLA-5 was constantly expressed during maturation. Furthermore, the enhancing effect by FN was inhibited in the presence of the Gly-Arg-Gly-Asp-Ser-Pro (GRGDSP) peptide but not in the presence of the connecting segment-1 (CS-1) peptide, suggesting that enhancement of AICD observed in CD4+ CD8+ thymocytes is mediated through VLA-5.

Presence of progenitors restricted to T, B, or myeloid lineage, but absence of multipotent stem cells, in the murine fetal thymus

The most immature population of fetal thymus (FT) cells has been shown to generate not only T but also B and myeloid cells. The present study was undertaken to clarify whether such a multipotent activity of the earliest population of FT cells is attributed to multipotent hemopoietic progenitors or to a mixture of lineage-restricted progenitors. Examination of individual FT progenitors by a recently established clonal assay system, which is able to determine the developmental potential of each progenitor toward T, B, and myeloid lineages, elucidated that a large majority of progenitors in FT were restricted to the T cell lineage. Presence of a small number of B or myeloid lineage-restricted progenitors was also disclosed. No multipotent progenitors, however, were detected in FT. These results are consistent with our recent finding that restriction of hemopoietic stem cells to T, B, and myeloid lineages takes place in the fetal liver.

Hepatocyte growth factor in vitreous fluid of patients with proliferative diabetic retinopathy and other retinal disorders

OBJECTIVE

To determine whether hepatocyte growth factor (HGF) is elevated in the vitreous fluid of patients with proliferative diabetic retinopathy (PDR).

RESEARCH DESIGN AND METHODS

Vitreous fluid samples were obtained at the time of vitreoretinal surgery from 73 eyes of PDR patients and from 17 eyes of nondiabetic patients (control subjects) who had macular hole, rhegmatogenous retinal detachment, or epiretinal membrane (9, 4, and 4 eyes, respectively) but no associated proliferative vitreoretinopathy Stages of PDR were classified as active or quiescent. Concentrations of HGF and vascular endothelial growth factor (VEGF) in vitreous fluid were determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Intravitreous concentrations of HGF (median [range]) were significantly higher in diabetic patients with PDR (6.00 ng/ml [0.75-22.21) than in control patients (2.86 ng/ml [0.75-5.801). Intravitreous concentrations of VEGF were also higher in diabetic patients with PDR (1.62 ng/ml [0.15-7.91) than in control patients (0.16 ng/ml [0.160.29]). Both VEGF and HGF concentrations were significantly higher in patients with active retinopathy than in those with quiescent retinopathy However, vitreous concentrations of HGF were unrelated to those of VEGE CONCLUSIONS: We found that levels of HGF in vitreous fluid of PDR patients are significantly higher than in nondiabetic patients and that the levels of HGF are elevated in the active PDR stage. This suggests that HGF stimulates or perpetuates neovascularization in PDR.

Effect of acarbose on postprandial lipid metabolism in type 2 diabetes mellitus

The effect of acarbose, an alpha-glucosidase inhibitor, on postprandial glucose and lipid metabolism was investigated in patients with type 2 diabetes mellitus. Twenty patients (10 men and 10 women) with type 2 diabetes mellitus were studied. A test meal was taken with or without 100 mg of acarbose. The levels of plasma glucose, and serum immunoreactive insulin, lipids, apolipoproteins, and remnant-like particle cholesterol were investigated. Acarbose inhibited the postprandial increase of both plasma glucose and serum immunoreactive insulin. Acarbose also significantly suppressed the increase of serum triglycerides at 60, 90, and 120 min (P < 0.05 to P < 0.01), and the increase of serum remnant-like particle cholesterol at 60 and 120 min (P < 0.05). Acarbose inhibited the postprandial decline of apolipoprotein C-II, and decreased the postprandial serum apolipoprotein C-III level. These results suggest that acarbose may improve postprandial hyperlipidemia as well as postprandial hyperglycemia in patients with type 2 diabetes mellitus.

Anti-Helicobacter pylori agents. 2. Structure activity relationships in a new series of 2-alkylguanidino-4-furylthiazoles

SAR for antimicrobial activity against H. pylori was investigated in a new series of 2-alkylguanidino-4-furylthiazoles. Of the compounds obtained, cyclohexylmethyl and ethoxyethyl derivatives were identified as a novel class of anti-H. pylori agents which possessed potent and selective antimicrobial activity against H. pylori. These compounds also showed gastric antisecretory activity.

In vitro generation of lymphohematopoietic cells from endothelial cells purified from murine embryos

We have investigated the lymphohematopoietic potentials of endothelial cells (EC) and hematopoietic cells (HPC) sorted from embryos. Expression of VE-cadherin, CD45, and Ter119 was used to distinguish EC (VE-cadherin+CD45-Ter119-) from HPC (VE-cadherin-CD45+). Thus defined, EC population takes up acetylated LDL and coexpresses CD31, Flk1, and CD34. In E9.5 embryos, EC from yolk sac (YS) and the embryo proper generate blood cells, including lymphocytes. Thus, lymphohematopoietic EC do exist in the embryo, and they are generated both in YS and the embryo proper. On the other hand, HPC with lymphopoietic potency appear first in the embryo proper. These findings implicate involvement of multiple environmental cues for acquiring lymphopoietic competency during differentiation of HPC.

Bioactive bone cement: effect of the amount of glass-ceramic powder on bone-bonding strength

We examined the influence of the proportion of glass-ceramic powder in a bioactive bone cement of our formula on the bone-bonding ability of cement. Changes in cement bonding with time also were examined. The bioactive bone cement consisted of MgO-CaO-SiO2-P2O5-CaF2 glass-ceramic powder (AW-GC powder) and bisphenol-alpha-glycidyl methacrylate (Bis-GMA)-based resin. AW-GC powder was added to the cement as 0%, 30%, 50%, 70%, and 80% w/w. Rectangular plates (2 x 10 x 15 mm) of each cement with polished surfaces were implanted into the proximal metaphysis of the tibiae of male rabbits, and the failure load was measured by detaching tests 10 and 25 weeks after implantation. The failure loads of each cement were 0% = 0.03, 30% = 1.52, 50% = 2.67, 70% = 3.56, and 80% = 5.59 kg at 10 weeks, and 0% = 0.05, 30% = 1.68, 50% = 2.77, 70% = 3.80, and 80% = 6.37 kg at 25 weeks. Observation of the cement-bone interface revealed that all bioactive bone cements (30%-80%) formed direct contact with bone whereas intervening fibrous tissue was observed in all specimens of the 0% group. By scanning electron microscopy, all bioactive bone cements (30%-80% groups) showed direct contact with bone at the cement-bone interface. In the 0% group, direct contact with bone at the cement-bone interface was not observed. By electron-probe microanalysis, a Ca-P-rich layer was not detected at the cement-bone interfaces of the 30%-70% bioactive bone cements, but in some samples of the 80% cement specimens a thin Ca-P-rich layer (3 microns thick) was observed at the interface at 10 and 25 weeks after implantation. These results show that all of the bioactive bone cements tested had the ability to bond to bone and to function as bioactive composites of ceramics and polymers.

Absence of p53 overexpression and favorable response to cisplatin-based neoadjuvant chemotherapy in urothelial carcinomas

It has been controversial whether cancer cells harboring loss or inactivation of the tumor suppressor p53 are resistant or sensitive to DNA-damaging agents including cisplatin and doxorubicin. Overexpression of mdm2 oncoprotein, a negative regulator of p53, is assumed to be an alternative to p53 dysfunction. Archival urothelial carcinoma specimens obtained from 60 patients prior to cisplatin-based chemotherapy were immunohistochemically studied for overexpression of p53 and mdm2. Thirty-two patients (group I) were treated with chemotherapy in the neoadjuvant setting, while 28 patients (group II) underwent chemotherapy for distant metastases or inoperable locoregional tumors. In group I, the responsiveness was correlated with staining status of p53 (P=0.0225) and the combination of p53 and mdm2 (P=0.0497). Negative staining of p53 and negative for both p53 and mdm2 could have predicted favorable response to chemotherapy in 16 of 18 (88.9%) and in 12 of 13 (92.3%) tumors, respectively. On the other hand, p53-positive and p53 and/or mdm2-positive staining could have predicted poor response only in 7 of 14 (50.0%) and 8 of 19 (42.1%) tumors, respectively. Disease-specific survival of the p53-negative group was significantly superior to that of the p53-positive group (P=0.0086). Difference in survival did not become more significant when overexpression of mdm2 was taken into consideration (P=0.0456). In contrast, in group II, there was no correlation of responsiveness to chemotherapy or survival with p53- or p53/mdm2-staining status. The patients with urothelial carcinomas negative for overexpression of p53 will benefit from neoadjuvant chemotherapy. From clinical viewpoint, however, p53 status alone or the combination of p53 and mdm2 status is not enough to identify those patients who will not benefit from the treatment.

In SCID-hu mice, passive transfer of a humanized antibody prevents infection and atrophic change of medulla in human thymic implant due to intravenous inoculation of primary HIV-1 isolate

Using SCID-hu mice, it was tested whether humanized mAb Rmu5.5 could prevent infection by HIV-1 i.v. inoculation. The Ab that recognizes the IHIGPGRAFYT motif in the principal neutralizing determinant (PND) of HIV(MN), as well as the original mouse mAb mu5.5, neutralized HIV(MN) with high activity. Seven primary field isolates from Japanese hemophiliacs seropositive for HIV-1 clade B were compared for their reactivities to Rmu5.5. Rmu5.5 was effective, particularly against the viruses that matched amino acid sequences of the PND region of HIV-1, and it completely neutralized primary isolates. Moreover, the passive transfer of the Ab elicited protection against challenge by the primary isolates in SCID-hu or hu-PBL-SCID mice after i.v. inoculation with the virus by both quantitative PCR and PBMC-based virus isolation in vitro. Further, inoculation with the Ab also prevented the atrophic change in the medulla of the thymic transplant that was induced by i.v. inoculation of the virus. Thus, the humanized neutralizing Ab Rmu5.5 appears to protect SCID-hu mice from infection by primary field isolates.

[Regional difference in the etiology of liver cirrhosis in Iwate]

To assess regional differences in the etiology of liver cirrhosis in Iwate, we analyzed 324 patients with liver cirrhosis treated at various hospitals. The etiology was HCV 44.8%, HBV 11.1%, HBV + HCV 4.6%, alcohol 27.5% (including heavy drinkers 17.9%), PBC 1.5% and non-B non-C 10.5% in Iwate. The incidence of alcoholic cirrhosis was higher than that in other prefectures, while that of HCV was lower. Especially in the northern area of Iwate, the rate of alcoholic cirrhosis was very high (39.1%--including heavy drinkers 21.8%) while viral cirrhosis was relatively low. Although the alcohol consumption volume in Iwate was not very high, marked alcohol consumption, especially shochu, was observed in the northern area of Iwate. The volume and kind of alcohol consumed in each area differed, and the etiology of liver cirrhosis differed regionally in Iwate. Thus, we should consider these districts and levels of alcohol consumption when treating patients with liver cirrhosis.

Probes for narcotic receptor-mediated phenomena. 25. Synthesis and evaluation of N-alkyl-substituted (alpha-piperazinylbenzyl)benzamides as novel, highly selective delta opioid receptor agonists

A series of N-alkyl- and N,N-dialkyl-4-[alpha-[(2S,5R)-4-allyl-2,5-dimethyl-1-piperazinyl] benzyl]-benzamides were synthesized and evaluated for binding affinities at mu, delta, and kappa opioid receptor subtypes. Several compounds (2e,f,h,i,m) strongly bound to the delta receptor with IC50 values in the nanomolar range. On the other hand, the binding affinities of these compounds for the mu and kappa receptors were in the micromolar or greater range indicating excellent delta opioid receptor subtype selectivities. In this series, two important structure-activity relationships were found for the delta receptor binding affinity. First, the spatial orientation of the alpha-benzylic position influenced the affinities with the alpha R derivatives 2a-n generally showing more than 10-fold greater affinity than the alpha S derivatives 3a-n. Second, the binding affinities were strongly influenced by the number of alkyl substituents on the amide nitrogen. N-Monoalkylbenzamide derivatives 2b-d showed lower affinity than N,N-dialkylbenzamide derivatives 2e-n, and the N-unsubstituted benzamide derivative 2a had the lowest affinity for the delta receptor in the series. The dramatic effect of the amide group substitution pattern on the binding affinity for the delta receptor strongly suggests that the amide function is an important structural element in the interaction of this series of compounds at the delta receptor. Selective compounds in this series were examined for binding affinity in cloned human mu and delta receptors. The results obtained generally paralleled those from the rat brain binding assay. Compounds 2e,f with potent delta binding affinities and high delta selectivities were shown to be delta agonists with high selectivity by studies in the guinea pig ileum (GPI) and mouse vas deferens (MVD) preparations. Compound 2f was the most selective compound in the rat brain and GPI/MVD assays with 1755- and 958-fold delta vs mu selectivity, respectively.

Anti-Helicobacter pylori agents. 1. 2-(Alkylguanidino)-4-furylthiazoles and related compounds

A series of 2-(alkylguanidino)-4-[5-(acetamidomethyl)furan-2-yl]thiazoles and related compounds were synthesized and evaluated for antimicrobial activity against Helicobacter pylori, inhibitory effect on gastric acid secretion, and histamine H2-receptor antagonist activity. Introduction of alkyl substituents on the guanidino moiety resulted in a significant increase in antimicrobial activity, which was associated with the alkyl chain length. Of the compounds obtained, the n-hexylguanidino derivative 13 demonstrated a 250-fold improvement in activity (MIC = 0.11 micrograms/mL) over the unsubstituted guanidino derivative 7. Alkyl-substituted guanidino derivatives also displayed gastric antisecretion and H2-antagonist activities. However, a simple correlation between the alkyl chain length and the activities was not found in these assays. Replacement of the guanidine with other bioisosteric groups (thiourea, urea, or (dimethylamino)methyl) resulted in loss of all activities tested. Thus the guanidino moiety was found to be essential for activity in this series of compounds.

Direct evidence for the commitment of hematopoietic stem cells to T, B and myeloid lineages in murine fetal liver

We established an experimental system in vitro to examine the developmental capacity of individual hematopoietic progenitors to generate T, B and myeloid (M) cells. By using this system we analyzed the process of lineage commitment of hematopoietic progenitors in murine fetal liver (FL). It is known that small numbers of B and M cells, in addition to T cells, are generated in a co-culture of hematopoietic progenitors and a deoxyguanosine-treated fetal thymus (FT) lobe. We tried to enhance the growth of B and M cells by the addition of IL-7, IL-3 and stem cell factor into the co-culture. This cytokine-supplemented FT organ culture was used to examine the developmental capacity of individual hematopoietic progenitors in FL. Single cells of lineage marker (Lin)-c-kit+Sca-1+ (Sca-1+) and Lin-c-kit+Sca-1-(Sca-1-) populations from the FL harvested at day 12 of gestation were cultured for 10 days, and the phenotypes of cells generated in each lobe were analyzed with a flow cytometer. All progenitors in the Sca-1- population were shown to be committed to generate only T, B or M cells. On the other hand, multipotent progenitors, which are capable of generating T, B and M cells, as well as unipotent progenitors committed to the T, B or M lineage were found in the Sca-1+ population. Bipotent progenitors generating M and T cells and those generating M and B cells were also found in the Sca-1+ population, which probably represent progenitors in the process of commitment. However, no bipotent progenitors generating T and B cells were detected.

T cell progenitors in the murine fetal liver: differences from those in the adult bone marrow

We compared the T cell generation from progenitors (T-progenitors) in the fetal liver (FL) with those in the fetal thymus (FT) and adult bone marrow (BM) by culturing these T-progenitors with hematopoietic cell-depleted FT lobes. As has previously been noted, 15-20 days were required for BM T-progenitors to give rise to CD4+ and/or CD8+ T cells. In marked contrast, only 7-10 days were enough for FL T-progenitors to produce those T cells. The kinetics of T cell differentiation from sorted c-kit+Lin- FL cells were quicker than those of BM cells and slower than those of FT cells. These results have indicated that prethymic FL T-progenitors are distinct from both prethymic BM T-progenitors and thymic FT T-progenitors in reference to their differentiational stage. Moreover, these FL type T-progenitors exist in the liver during fetal age from Day 12 of gestation but not in the bone marrow of 1-week-old neonatal mice, suggesting that the fetal liver as a hematopoietic organ could induce the early T cell differentiation of progenitor cells.