Ultraviolet emission from a diamond pn junction

We report the realization of an ultraviolet light-emitting diode with the use of a diamond pn junction. The pn junction was formed from a boron-doped p-type diamond layer and phosphorus-doped n-type diamond layer grown epitaxially on the 111 surface of single crystalline diamond. The pn junction exhibited good diode characteristics, and at forward bias of about 20 volts strong ultraviolet light emission at 235 nanometers was observed and was attributed to free exciton recombination.

Observation of rho/omega meson modification in nuclear matter

We measured the invariant mass spectra of electron-positron pairs in the target rapidity region of 12-GeV p+A reactions. We have observed a significant difference in the mass spectra below the omega meson between p+C and p+Cu interactions. This difference indicates that the spectral shape of mesons is modified at normal nuclear-matter density.

Inhibitors of arachidonic acid metabolism have variable effects on calcium signaling pathways

The metabolic pathways of arachidonic acid (AA) have been shown to be important in the regulation of cellular function. Several studies have demonstrated both direct and indirect effects of products of these pathways in the regulation of vascular actions, and in particular on signaling pathways. Because intracellular calcium concentration is a significant mediator of stimulus-coupled signal transduction, we investigated the effects of AA pathway inhibitors on angiotensin II (Ang II)-induced calcium mobilization in cultured rat vascular smooth muscle cells (VSMC). Thus, specific calcium pools were examined for differential effects resulting from inhibitors of the three major pathways of AA metabolism. Inhibition of lipoxygenase (LO) with 2.5 micromol/L of 5,8,11 eicosatriynoic acid (ETI), cyclooxygenase (CO) with 2 micromol/L of ibuprofen (IBU), and cytochrome P-450 (P450) with 1 micromol/L of 7-ethoxyresorufin (7ER) all reduced total Ang II-induced intracellular calcium transients ([Ca2+]i) in fura 2-loaded cultured rat VSMC. However, the sites of action affected were unique for each inhibitor. Pretreatment of VSMC with either ETI or IBU inhibited thapsigargin (TG) (1 micromol/L)-sensitive calcium increments (control; 118.0 +/- 33.1 nmol/L, n = 9, ETI; 34.7 +/- 4.8 nmol/L, n = 9, IBU; 40.3 +/- 8.8 nmol/L, n = 8, P < .05 v control). Both caffeine (CAF) and ryanodine (RY) treatment attenuated Ang II-induced [Ca2+]i; however, pretreatment with ETI, IBU, or 7ER did not alter this effect. In other studies, the LO inhibitor ETI attenuated Ang II-induced Ca2+ influx, whereas inhibitors of CO and P450 pathways had no effect. These data show that 1) E

Impact of insulin resistance and nephropathy on homocysteine in type 2 diabetes

OBJECTIVE

To assess the impacts of insulin resistance and renal function on plasma total homocysteine (tHcy) levels in patients with type 2 diabetes with a wide range of nephropathy.

RESEARCH DESIGN AND METHODS

Plasma tHcy levels were measured using the enzyme immunoassay method in 75 patients with type 2 diabetes and compared with those in 54 healthy control subjects. Insulin sensitivity indexes were assessed in patients with type 2 diabetes by hyperinsulinemic-euglycemic clamp using artificial pancreas.

RESULTS

Plasma tHcy levels and their log-translormed values (log tHcy) were significantly higher in all patients with diabetes than in control subjects (tHcy, 12.0 +/- 0.7 [SE] vs. 8.7 +/- 0.3 micromol/l, P < 0.0001; log tHcy, 1.040 +/- 0.021 vs. 0.920 +/- 0.016 micromol/l, P < 0.0001). Plasma tHcy levels in patients with diabetes were significantly increased according to degree of nephropathy (P < 0.0001). On simple regression analyses, log tHcy correlated with insulin sensitivity indexes (r = -0.319, P = 0.005) as well as creatinine clearance (r = 0.634, P < 0.0001) in all patients with diabetes. Multiple regression analyses showed that insulin sensitivity indexes (beta = -0.245) as well as creatinine clearance were independent contributors to log tHcy in all patients with diabetes (R2 = 0.750, P < 0.0001). For the 59 patients with diabetes with creatinine clearance >60 ml/min, insulin sensitivity indexes were also shown to be a significant contributor to log tHcy (beta = -0.438, R2 = 0.561, P < 0.001).

CONCLUSION

Insulin resistance and renal function are independent determinants of tHcy levels in patients with type 2 diabetes.

Quantitative analysis of fushi tarazu factor 1 homolog messenger ribonucleic acids in the pituitary of salmon at different prespawning stages

Steroidogenic factor 1 (SF-1) or Ad4BP is a member of the fushi tarazu factor 1 (FTZ-F1) family and an orphan nuclear receptor that plays an important role in the hypothalamus-pituitary-gonadal axis and the adrenal cortex. Although its critical role in the differentiation of adrenals, gonads, and pituitary gonadotropes has been well demonstrated, regulatory function of SF-1 during sexual maturation is yet to be examined. To investigate the potential role of SF-1 in sexual maturation, expression of two salmon FTZ-F1 homolog genes, sFF1-I and sFF1-II, was examined in the pituitaries of chum and sockeye salmons, using specific and sensitive RNase protection assays. Only sFF1-I mRNA was found in the pituitary and other organs, such as the ovary, spleen, liver, brain, and skeletal muscle. In chum salmon during upstream migration from the bay to the hatchery, the level of sFF1-I mRNA in the male fish was increased on the midway in the river, where the levels of gonadotropin alpha- and II beta-subunit mRNAs were increased. In maturing sockeye salmon, the expression of the sFF1-I gene was elevated in the mature male fish, but the administration of GnRH analog did not further enhance the expression. These results indicate that sFF1-I gene expression in the pituitary is upregulated in maturing salmon, and this upregulation may not depend on GnRH.

Effects of prostaglandin E1 on hepatic blood flow in conscious dogs with chronic biliary obstruction

To evaluate the effects of prostaglandin E1 (PGE1) on the hepatic circulation in cholestasis, hepatic arterial blood flow (HAP), portal venous blood flow (PVF), cardiac output, and heart rate during PGE1 infusions were investigated before and 2 weeks after biliary obstruction in conscious dogs by a transit-time ultrasonic flowmeter. In the control period, HAF and PVF increased dose dependently with the infusion of PGE1 from 0.05 to 0.5 micrograms/kg/min. During the biliary obstruction period, a lower dose of PGE1 increased HAF and PVF. The plasma concentration level of PGE1 during the infusion of PGE1 was significantly higher at each dose in the cholestatic animals. These results suggest that the metabolism of PGE1 is attenuated by cholestasis. Plasma PGE1 concentrations should be useful in deciding the optimal dose of PGE1.

Impaired collagen gel contraction with cultured skin fibroblasts from patients with systemic sclerosis

We investigated the capacity of skin fibroblasts, derived from 9 patients with systemic sclerosis (SSc), to contract collagen lattices in a three-dimensional culture system. In comparison with control fibroblasts (N = 8), more than 30% of SSc fibroblasts exhibited markedly impaired ability to contract collagen lattices. The expression of alpha2beta1 integrins and integrin-mediated signals were not significantly different between normal and SSc fibroblasts. Although the underlying mechanisms remain to be determined, our present data provide evidence that certain aspects of interaction with collagen are impaired in SSc fibroblasts.

A genetic linkage map of the MSM Japanese wild mouse strain with restriction landmark genomic scanning (RLGS)

A high-resolution genetic map of the Mus musculus molossinus (MSM) Japanese wild mouse strain was constructed with restriction landmark genomic scanning (RLGS) and compared with that of the laboratory strain C3H. MSM is phylogenetically 1 million years apart from common laboratory mouse strains and is distinctly resistant to chemical carcinogenesis. Since it exhibits frequent genetic polymorphisms with laboratory mice but can still be easily crossed with laboratory strains, hybrids between MSM and carcinogen-sensitive laboratory mouse strains provide excellent materials for analysis of modifier genes and genetic changes during carcinogenesis. We have generated MSM backcross progeny with the C3H strain, which is extremely sensitive to hepatocarcinogenesis, to construct the present map. RLGS profiles with two combinations of restriction enzymes (NotI-PvuII-PstI, NotI-PstI-PvuII) yielded more than 2000 spots each. The polymorphism rate was about 39.2%, and of a total of 1732 polymorphic spot loci identified, 1371 could be assigned to specific chromosomes by comparison with 79 microsatellite marker loci. Thus, 1450 loci, on all chromosomes except for Y, effectively mapped 90% of the genome (1431.7 cM length). Although some spots might be derived from the same NotI site, each NotI site potentially generating two fragments, the presence of at least 515 loci groups with different progeny distribution patterns dispersed through the genome with an average spacing of 3 cM, means that this genetic map should be useful for analysis of various biological phenomena, including carcinogenesis and ontogenesis, at the gene level.

Spontaneously regressed Kaposi's sarcoma and human herpesvirus 8 infection in a human immunodeficiency virus-negative patient

Kaposi's sarcoma occurring in a 78-year-old woman, with the absence of the human immunodeficiency virus infection, was correctly diagnosed by immunohistochemistry using anti-human herpesvirus 8 (HHV8) antibody (PA1-73N) for the first time. The patient suffered from chronic respiratory failure and was treated with a low dose of steroids for 2.5 years. After her medication dosage was increased for the exacerbation of the respiratory failure, multiple skin tumors in her feet and legs suddenly developed. Histopathologically, skin tumors were suspected as Kaposi's sarcoma at the first biopsy and reactive angiomatosis at the second biopsy. Polymerase chain reaction and immunohistochemistry, however, revealed the presence of HHV8 DNA fragment and positive staining in the majority of spindle cells in the skin tumors. Serological examination confirmed the positivity of anti-HHV8 antibodies. HHV8 infection and steroid-induced immunosuppression, as well as environmental factors played a role in the development of Kaposi's sarcoma in this patient, because she was born in Okinawa, which is a well-known endemic area of Kaposi's sarcoma in Japan. As her general condition improved, the skin lesions regressed without any specific treatment, and disappeared completely 8 months later, in which regression may be associated with evidence of numerous CD8 cell infiltration in the second biopsy tissues. No recurrence was observed during the following 6 month follow up.

Malignant transformation and EGFR activation of immortalized mouse liver epithelial cells caused by HBV enhancer-X from a human hepatocellular carcinoma

We have previously observed that all human hepatocellular carcinomas (HCCs) from HBV carriers examined had the integrated X region. In this study, HBV DNA was isolated from an integration site in one HCC that had a single, very small integrated viral DNA including the X region, but it had no expression of X gene as poly(A)RNA. It was found that HBV DNA was present between alphoid repetitive sequences, and it included Enhancer and X regions, encompassing the adr sequence from 910 to 1811. Nucleotides for 8 amino acids at the 3' end, a stop codon of X gene and a poly(A) signal downstream of X gene were lost by integration, and nucleotides for 7 amino acids and a stop codon were substituted by a connected alphoid sequence. When this cloned HBV DNA was transfected with an expression vector to an immortalized mouse liver epithelial cell line, MLE-10, malignant transformation occurred. Transformants having expressed poly(A)RNA of the X gene showed anchorage-independent growth in soft agar and tumor formation in the subcutis of nude mice. The mRNA level of EGFR was found to be remarkably enhanced in X-transformed cells, in contrast with the absence of this mRNA in parental and ras-transformed MLE-10. Our data provide evidence that the Enhancer-X region alone is the key contributor to the malignant change of pre-malignant liver cells in HBV carriers through activation of some specific genes, such as EGFR.

[Cyclophosphamide-induced renal pelvic tumor--a case report]

We report a case of transitional cell carcinoma in the left renal pelvis, which occurred in a 24-year-old man. He had been treated with cyclophosphamide (CPM) for a period of 27 months for retroperitoneal rhabdomyosarcoma diagnosed at the age of 10. At first 1.2 g CPM had been given twice intravenously for 3 months, followed by oral administration of 41 g CPM for 23 months. Drip infusion pyelography revealed a filling defect in the left renal pelvis. A left renal pelvic tumor was strongly suspected on computerized tomography and magnetic resonance imaging. Left nephroureterectomy was then performed. Histological diagnosis of the left renal pelvic tumor was transitional cell carcinoma, grade 2, pT1N0M0. No recurrence was defected 17 months later. This case seems to be the second case of cyclophosphamide-induced upper urothelial carcinoma reported in Japan.

Malignant transformation and EGFR activation of immortalized mouse liver epithelial cells caused by HBV enhancer-X from a human hepatocellular carcinoma

We have previously observed that all human hepatocellular carcinomas (HCCs) from HBV carriers examined had the integrated X region. In this study, HBV DNA was isolated from an integration site in one HCC that had a single, very small integrated viral DNA including the X region, but it had no expression of X gene as poly(A)RNA. It was found that HBV DNA was present between alphoid repetitive sequences, and it included Enhancer and X regions, encompassing the adr sequence from 910 to 1811. Nucleotides for 8 amino acids at the 3' end, a stop codon of X gene and a poly(A) signal downstream of X gene were lost by integration, and nucleotides for 7 amino acids and a stop codon were substituted by a connected alphoid sequence. When this cloned HBV DNA was transfected with an expression vector to an immortalized mouse liver epithelial cell line, MLE-10, malignant transformation occurred. Transformants having expressed poly(A)RNA of the X gene showed anchorage-independent growth in soft agar and tumor formation in the subcutis of nude mice. The mRNA level of EGFR was found to be remarkably enhanced in X-transformed cells, in contrast with the absence of this mRNA in parental and ras-transformed MLE-10. Our data provide evidence that the Enhancer-X region alone is the key contributor to the malignant change of pre-malignant liver cells in HBV carriers through activation of some specific genes, such as EGFR.

Inverse relationship between circulating oxidized low density lipoprotein (oxLDL) and anti-oxLDL antibody levels in healthy subjects

Oxidized low density lipoprotein (oxLDL) has been implicated in the pathogenesis of atherosclerosis. Recent studies have shown that immunization of animals with oxLDL results in suppression of atherogenesis. Antibody against oxLDL (oxLDL Ab) is detectable in human sera, although its biological significance is not well established. We examined the relationship between oxLDL Ab titer and circulating oxLDL level in 130 healthy Japanese subjects. OxLDL was measured as apolipoprotein (apo) B-containing lipoproteins carrying oxidized phosphatidylcholines by a sensitive ELISA. IgG class oxLDL Ab titer was measured by ELISA. Plasma oxLDL concentration was very low and it corresponded on average to one to two out of 1000 apoB-containing lipoproteins in plasma. Plasma oxLDL correlated positively with LDL cholesterol and inversely with oxLDL Ab titer. These associations remained significant and independent in multiple regression analysis including age, gender, smoking, and high-density lipoprotein cholesterol. These data indicate that healthy subjects have a very low concentration of oxLDL in the circulation, and that oxLDL Ab titer is in an inverse relationship with plasma oxLDL concentration in this population. Although these results suggest that oxLDL Ab may play a role in maintaining the low level of plasma oxLDL, its role in atherogenesis awaits further studies.

Correlation between the intima-media thickness of the carotid artery and aortic pulse-wave velocity in patients with type 2 diabetes. Vessel wall properties in type 2 diabetes

OBJECTIVE

The aim of this study was to assess the relationship between atherotic (structural) and sclerotic (functional) changes in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Aortic distensibility and carotid intimal-media thickness (IMT) were evaluated using carotid-femoral aortic pulse-wave velocity (a-PWV) and high-resolution B-mode ultrasonography in 271 patients with type 2 diabetes and 285 age-matched control subjects.

RESULTS

a-PWV and carotid IMT were significantly higher in the patients than in the control subjects in all age-groups (P < 0.0001, respectively). The carotid IMT and a-PWV were significantly correlated with age in both the patients with type 2 diabetes and control subjects. There was a significant positive relationship between the carotid IMT and a-PWV in both the patients (r = 0.482, P < 0.0001) and control subjects (r = 0.424, P < 0.0001). The slope of the regression line for the carotid IMT to the a-PWV was significantly steeper in the diabetic patients than in the control subjects (P < 0.05). Multiple regression analysis in all subjects showed that age, diabetic state, and cigarette smoking were independently common risk factors for the increase in carotid IMT and a-PWV. In the diabetic patients, the independent risk factors associated with the carotid IMT were age, hyperlipidemia, and duration of diabetes (R2 = 0.232, P < 0.0001), while those associated with a-PWV were age and duration of diabetes (R2 = 0.334, P < 0.0001).

CONCLUSIONS

The results indicated that diabetic patients showed more advanced changes in atherosis than that in sclerosis as compared with age- and sex-matched control subjects. Such atherotic changes in diabetic patients may be associated with hyperlipidemia.

First systematic chiral syntheses of two pairs of enantiomers with 3,5-dihydroxyheptenoic acid chain, associated with a potent synthetic statin NK-104

First systematic chiral syntheses of two pairs of enantiomers with 3,5-dihydroxyheptenoic acid chain, associated with a potent synthetic statin NK-104 are reported. A pair of syn diol isomers (NK-104 and its enantiomer) was obtained efficiently by diastereomeric resolution. The synthesis of a pair of anti diol isomers (3-epimer and 5-epimer) was accomplished effectively by the asymmetric aldol reaction followed by anti stereoselective reduction as key steps. Their purity determinations were effected by chiral HPLC analysis.

Impaired endothelium-dependent vascular responses of retinal and intrarenal arteries in patients with type 2 diabetes

Endothelial dysfunction has been implicated in the pathogenesis of diabetic microangiopathies such as retinopathy and nephropathy as well as macrovascular diseases. The aim of the current study was to determine whether endothelial function in the retinal and renal arteries is impaired in type 2 diabetes mellitus. We examined the effects of an intravenous infusion of L-arginine and a sublingual administration of nitroglycerin on the brachial, retinal, and interlobar arterial hemodynamics in 20 type 2 diabetic patients (10 with normoalbuminuria and 10 with microalbuminuria) and 10 aged-matched control subjects. Despite no difference in the nitroglycerin-induced vascular response of the brachial or retinal artery among the 3 groups, the L-arginine-induced vascular response of each artery was significantly lower in both the normoalbuminuric and microalbuminuric patients than in the control subjects and the microalbuminuric patients showed the lowest value among the 3 groups (P<0.01, each artery, respectively). The L-arginine-induced vascular response of each artery was significantly correlated with HbA1c levels (brachial artery, r=0.617, P=0.0003; retinal artery, r=0.599, P=0.0005; interlobar artery, r=0.636, P=0.0002). In addition, stepwise multiple regression analysis of all subjects showed that HbA1c level was an independent determinant for the L-arginine-induced vascular response of each artery. The results showed that the endothelium-dependent vascular responses of the retinal and intrarenal arteries as well as the brachial artery were impaired in diabetic patients before the clinical manifestation of diabetic nephropathy, and suggest that endothelial dysfunction in these arteries is associated with hyperglycemia in these patients.

Detection of WT1 mRNA in urine from patients with kidney diseases

Detachment of glomerular epithelial cells (GEC) from glomerular basement membrane (GBM) could account for a part of the pathogenic mechanism of proteinuria seen in primary and secondary renal diseases. The Wilms' tumour suppresser gene (WT1) is strictly expressed in GEC in the adult kidney. Mutations of WT1 gene have been implicated in progressive renal damage. Utilizing nested RT-PCR we detected mRNA of WT1 in the urine of patients with renal diseases. Seven of 20 (35%) chronic glomerulonephritis (CGN), eight of 20 (40%) diabetes mellitus (DM) with proteinuria, and two of 24 (8.3%) rheumatic diseases were WT1 positive. Interestingly, only one of 51 (2%) DM without proteinuria was WT1 positive. None of the healthy volunteers or cystitis patients were WT1 positive. This is the first report describing the detection of endogenous WT1 mRNA, an important gene in progressive renal failure, from patients' urine. This technique could be a powerful tool in the search for information about glomerular damage in clinical settings as well as for WT1 mutations or isoform imbalance at the research level without renal biopsy.

Glomerular overexpression and increased tyrosine phosphorylation of focal adhesion kinase p125FAK in lupus-prone MRL/MP-lpr/lpr mice

Much progress has been made in understanding how mammalian cells receive a diverse array of external stimuli and convert them into intracellular biochemical signals. Such efforts have identified a large number of signalling molecules. However, our knowledge is limited as to their pathophysiological role in particular diseases. We demonstrate herein that an integrin-linked signalling molecule, focal adhesion kinase p125FAK (FAK), is overexpressed in glomeruli of lupus-prone MRL/MP-lpr/lpr (MRL-lpr) mouse as compared to its congeneic MRL-+/+ strain. Increased expression was specifically demonstrated in glomeruli but not in other tissues examined. The overexpression was observed in 16-week-old MRL-lpr mice with active nephritis, as well as in younger animals at 4 weeks of age. Thus, the upregulation of FAK clearly preceded the clinical onset of nephritis. FAK in MRL-lpr glomeruli is highly tyrosine phosphorylated and is associated with adapter protein Grb2. Previous in vitro studies have shown that the association of FAK/Grb2 links cell adhesion to the Ras pathway, which ultimately stimulates mitogen-activated protein (MAP) kinase, an important regulator of cell proliferation. In accordance, we observed constitutive MAP kinase activation in MRL-lpr glomeruli. Our findings suggest that signalling pathways involving FAK are activated in MRL-lpr glomeruli, and are likely to play a role in the development and progression of autoimmune-mediated murine nephritis.

Antitumor mechanisms and metabolism of the novel antitumor nucleoside analogues, 1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl)cytosine and 1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl)uracil

The antitumor ribonucleoside analogues 1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl)cytosine (ECyd) and 1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl)uracil (EUrd), first synthesized in 1995, have strong antitumor activity against human cancer xenografts without severe side effects. Here, we studied the antitumor mechanisms of ECyd and EUrd using mouse mammary tumor FM3A cells in vitro and the mechanism of selective cytotoxicity of ECyd using human tumor xenografts in nude rats in vivo. In FM3A cells, ECyd and EUrd were rapidly phosphorylated to ECyd 5'-triphosphate (ECTP) and EUrd 5'-triphosphate (EUTP), which strongly inhibiting RNA synthesis. Cells treated with EUrd were later found to contain both EUTP and ECTP, and ECTP accumulated as the final product. Probably the uracil moieties of EUrd derivatives were efficiently converted to cytosine moieties in the cells. EUrd and its derivatives were minor metabolites in the cells treated with ECyd, so cytidine forms probably were not converted to uridine forms at the nucleoside or nucleotide stage. The ultimate metabolite of ECyd and EUrd, ECTP, is stable in cultured cells with a half-life of at least 3 days, so ECyd and EUrd are on a "closed" metabolic pathway to ECTP. These characteristics of ECyd and EUrd may be important for their antitumor activity. ECyd had strong and selective antitumor activity against the human tumor xenografts. ECyd-phosphorylating activity (uridine/cytidine kinase) in the xenografts was higher than that in the organs of the rats. This finding may account for the strong activity with mild side effects. ECyd and EUrd may be a new kind of antitumor nucleoside analogue for clinical use.

Commitment and differentiation of stem cells to the osteoclast lineage

Osteoclasts are hematopoietic cells which play important roles in bone remodeling and resorption. They have phenotypic characteristics of the monocyte/macrophage lineages. In this review we first describe the phylogeny of osteoclasts. Osteoclast generation is closely linked to the presence of bone tissues. The formation of bone cavities in aquatic animals is underdeveloped, even though they have cells which have the potential to differentiate into osteoclasts. Next we describe recent advances in our understanding of osteoclastogenesis that have resulted from the identification of critical molecules and mutated genes of osteopetrotic mice. Reports that transcriptional factors PU.1 and c-Fos are essential for commitment and (or) differentiation into the osteoclast lineage and novel culture systems, which have clarified some characteristics of osteoclast precursors, are also described. We are now able to induce mature osteoclasts from hematopoietic stem cells and even from totipotent embryonic stem cells. Cell lines that differentiate into osteoclasts are also available. Using these culture systems and cell lines, the interactions of osteoclasts with osteoblastic stromal cells, which produce critical molecules for osteoclastogenesis, have been studied. Very recently, one of these critical molecules, osteoclast differentiation factor/osteoprotegerin-ligand, was cloned. The presence of this factor and macrophage-colony-stimulating factor is sufficient to induce osteoclast development in cultures inoculated only with an osteoclast precursor cell line. We review the present status and the remaining questions in osteoclast biology.

Improvement of regional myocardial and coronary blood flow reserve in a patient treated with enhanced external counterpulsation: evaluation by nitrogen-13 ammonia PET

Enhanced external counterpulsation (EECP) is a noninvasive treatment for chronic stable angina, which works by recruiting and developing the coronary collateral vessels. Coronary perfusion and coronary flow reserve (CFR) were evaluated by nitrogen-13 (13N) ammonia positron emission tomography (PET) in a patient who had undergone EECP. The patient, who had 3-vessel coronary artery disease, required a percutaneous transluminal coronary angioplasty (PTCA) for the right coronary artery. The PTCA was successful, but 6 months later he again felt chest oppression. The coronary angiography showed re-stenosis at the PTCA site, and other progressive coronary stenosis. The patient was again treated with EECP for 35 h. The 13N-ammonia PET was performed both at baseline and during dipyridamole provocation, before and after EECP treatment. Coronary perfusion of each myocardial wall increased at the baseline (anterior: 0.52-0.75; septal: 0.48-0.66; lateral: 0.61-0.68; inferior: 0.46-0.57 ml min(-1) g(-1), and the CFRs in the septal and inferior walls (septal: 2.07-2.15; inferior: 1.99-2.06) also increased after the treatment. Thus, the EECP treatment improved both coronary perfusion at baseline and CFR, which suggests that it may be one of the choices for treatment of angina.

Homeostasis model assessment as a clinical index of insulin resistance in type 2 diabetic patients treated with sulfonylureas

OBJECTIVE

To investigate whether the insulin resistance index (IR) assessed by homeostasis model assessment (HOMA) is associated with the insulin resistance index assessed by euglycemic-hyperinsulinemic clamp (clamp IR) in type 2 diabetic patients who received sulfonylureas (SUs), as well as in those treated by diet alone.

RESEARCH DESIGN AND METHODS

Retrospectively, the association between HOMA IR and clamp IR was analyzed in 80 type 2 diabetic subjects (53 subjects treated with SUs and 27 subjects treated with diet alone). The 80 subjects, selected because they had not received insulin therapy, were among 111 diabetic participants in a clamp study for evaluation of insulin resistance from May 1993 to December 1997 in Osaka City University Hospital.

RESULTS

The HOMA IR showed a hyperbolic relationship with clamp IR. The log-transformed HOMA IR (all subjects, r = -0.725, P < 0.0001; SU group, r = -0.727, P < 0.0001; diet group, r = -0.747, P < 0.0001) correlated more strongly with clamp IR than did HOMA IR per se (all subjects, r = -0.594, P < 0.0001; SU group, r = -0.640, P < 0.0001; diet group, r = -0.632, P = 0.0004). The univariate regression line between log-transformed HOMA IR and clamp IR in the SU group did not differ from that in the diet group (slope, -6.866 vs. -5.120, P > 0.05; intercept, 6.566 vs. 5.478, P > 0.05). Stepwise multiple regression analyses demonstrated that the log-transformed HOMA IR was the strongest independent contributor to clamp IR (R2 = 0.640, P < 0.0001).

CONCLUSIONS

The HOMA IR strongly correlated with the clamp IR in type 2 diabetic patients treated with SUs as well as in those treated with diet alone.

Fyn and Lck tyrosine kinases regulate tyrosine phosphorylation of p105CasL, a member of the p130Cas docking protein family, in T-cell receptor-mediated signalling

We have previously shown that engagement of the T-cell receptor (TCR)/CD3 complex with anti-CD3 antibody induces tyrosine phosphorylation of p105CasL (CasL), a member of the p130Cas docking protein family. In the present work, we attempted to determine which protein tyrosine kinases (PTKs) regulate TCR-mediated phosphorylation of CasL. We show here that an association between CasL and two types of Src family PTKs, Fyn and Lck, is induced by anti-CD3 cross-linking of human H9 T cells. In contrast, ZAP-70, another PTK that also plays a critical role in the TCR signalling, failed to bind CasL, even after anti-CD3 stimulation. In vitro kinase assays revealed that Fyn and Lck, but not ZAP-70, were capable of phosphorylating CasL. Moreover, we found that CasL was constitutively hyperphosphorylated in vivo in splenocytes of MRL-MP-lpr/lpr mice, in which overproduction and excessive activation of Fyn and Lck have previously been shown to occur. Constitutive in vivo binding of CasL to both kinases was also demonstrated in lpr splenocytes. These results strongly suggest that CasL is a substrate for Fyn and Lck PTKs in TCR signal transduction.

Fibrolamellar carcinoma of the liver

We report a resected case of fibrolamellar carcinoma (FLC) of the liver that occurred in a 21 year-old Japanese male with a normal liver. Lymph node metastases around the common hepatic artery and the hepatic hilum were revealed by a post-operative histological examination. He was in good health 7 months after the surgery. This case demonstrates typical findings of FLC, radiologically and histologically. The details are described in this report. Moreover, after reviewing 12 Japanese cases, we emphasize the differential diagnosis of focal nodular hyperplasia (FNH) as the following: 1) Calcification is frequently seen in FLC. 2) The central scar of FLC is visualized as an area of low intensity on T2-weighted magnetic resonance imaging (MRI).

cDNA sequence analysis of monoclonal antibody FU-MK-1 specific for a transmembrane carcinoma-associated antigen, and construction of a mouse/human chimeric antibody

Mouse monoclonal antibody (MAb) FU-MK-1, raised against a human gastric adenocarcinoma, recognizes a transmembrane antigen, GA733-2, present on most adenocarcinomas and seems to be of potential utility for immunodiagnosis and immunotherapy of those cancers. However, an inherent problem in their in vivo application is the human anti-mouse antibody response. In this study, we cloned and sequenced the variable region genes of the heavy and light chains (V(H) and Vkappa) of FU-MK-1 using the reverse transcription-polymerase chain reaction method. Then, we constructed a mouse/human chimeric antibody, designated as Ch FU-MK-1, by fusing the FU-MK-1 V(H) and Vkappa genes to the human Cgamma1 and Ckappa genes, respectively, and by ligating the chimeric H and L chain genes to each other in a mammalian cell expression vector. The final gene construct was transfected into mouse non-Ig-producing hybridoma cells by electroporation. The Ch FU-MK-1 antibody thus prepared bound to human adenocarcinoma cells and competitively inhibited the binding of the parental FU-MK-1 to the adenocarcinoma cells. Ch FU-MK-1 also showed a potent antibody-dependent cell-mediated cytotoxicity (ADCC) with human peripheral blood mononuclear cells as effectors against the adenocarcinoma cells, indicating that this chimeric antibody seems to be suitable for in vivo therapeutic approaches.

Identification of metabolites of NK-104, an HMG-CoA reductase inhibitor, in rat, rabbit and dog bile

NK-104 is an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase with a very potent lipid-lowering effect. Biotransformation profiles of NK-104 in bile from rat, rabbit and dog given an intravenous infusion of NK-104 were investigated. Structural assignment was made by liquid chromatography (LC)-mass spectrometry (MS)-MS and proton NMR analyses. The predominant component was intact NK-104 in all the animals. At least eight other metabolites were present in rat, four in rabbit, and 10 in dog. These bile metabolites were purified and isolated by preparative HPLC. Biotransformation pathways elucidated for NK-104 were as follows: (a) lactonization ; (b) beta-oxidation of the side-chain; (c) hydroxylation of the quinoline ring; (d) conjugation with Beta-glucuronic acid and taurine. Beta-oxidative degradation of the side-chain in the case of other HMG-CoA reductase inhibitors is necessary for epimerization of the hydroxy group which has an R-configuration. However, M-16, glucuronide of the ketolactone derivative, was obtained as a key metabolite suggesting another beta-oxidation pathway for the side-chain.

Loss of imprinting of the insulin-like growth factor II gene in mouse hepatocellular carcinoma cell lines

We investigated expression of insulin-like growth factor II (Igf2) in primary cultured hepatocytes, liver epithelial (LE) cell lines derived from normal hepatocytes, and hepatocellular carcinoma (HCC) cell lines from crosses between C3H/HeJ (C3H) and Mus musculus molossinus mice (MSM). Igf2 mRNA was detected by reverse transcriptase-polymerase chain reaction in primary cultured hepatocytes from 5 d after the start of cultivation and in all 12 LE and 16 HCC cell lines. Analysis of the untranslated region of Igf2 exon 6, which contains polymorphic CA repeats, revealed that 13 of the 16 HCC cell lines had biallelic expression, whereas monoallelic expression was retained in the primary cultured hepatocytes and all 12 LE cell lines. The Igf2 transcripts contained exons 1-3 in all the HCC cell lines but only exons 2 and 3 in cultures of hepatocytes and LE cell lines, indicating difference in promoter use. However, the biallelic HCC cell lines did not have larger amounts of Igf2 mRNA and protein than did the monoallelic lines, suggesting that loss of imprinting may not be directly related to the level of Igf2 expression.

[Endopyelotomy with Acucise for secondary ureteropelvic junction obstruction: report of a case]

We report a case of successful endopyelotomy using the Acucise cutting balloon device for secondary ureteropelvic junction obstruction (UPJO). A 23-year-old man was hospitalized with the chief complaint of left lumbago and left hydronephrosis due to left UPJO. He underwent antegrade endopyelotomy with a nephroscope and open pyeloplasty. However, left lumbago and hydronephrosis did not show improvement. Acucise endopyelotomy was performed under epidural anesthesia. The operative time was 55 minutes and the hospital stay after the operation was 4 days. There were no operative complications and 3 months later, the operative results were satisfactory as determined by drip infusion pyelography and the disappearance of the lumbago.

Antibody-dependent difference in biodistribution of monoclonal antibodies in animal models and humans

The study was designed to clarify the difference in pharmacokinetics of monoclonal antibodies (mAb) in animal models and humans, and to elucidate the applicability of animal models. 99mTc-labeled murine mAb -- against carcinoembryonic antigen (designated BW431/26), and neural cell adhesion molecule (NE150) -- and one chimeric mouse/human mAb against nonspecific cross-reacting antigen (chNCA) were administered i.v. to normal mice and athymic mice (370 kBq, 400 ng) xenografted with human cancer cells expressing antigens, and into patients with tumor (925 MBq, 1 mg). The biodistribution of two of the three mAb (not 99mTc-BW431/26) differed clearly in mice and patients. 99mTc-NE150 showed specific uptake in xenografted tumor and otherwise a normal biodistribution; however, clinical examination showed increased uptake in the liver with rapid blood clearance (mean alpha half-life = 31.1 min) compared with 99mTc-BW431/26 (28.4 h). 99mTc-chNCA demonstrated increased blood clearance and renal excretion in both normal and athymic mice, with accumulation in tumors. Clinical examination showed rapid blood clearance (mean alpha half-life = 6.4 min) and increased uptake in the liver. High-performance liquid chromatographic analysis of 99mTc-chNCA revealed the immune complex in blood, suggesting uptake of the complex by the reticuloendothelial cells. The biodistribution of radiolabeled mAb in animal and human models was variable and specific for each of the three mAb. The results of animal studies with mAb should be evaluated carefully before being extrapolated to humans, on the basis of the nature of the mAb and interacting substances.

The characterization of cell death induced by 1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl) cytosine (ECyd) in FM3A cells

The characterization of cell death induced by 1-(3-C-ethynyl-beta-D- ribopentofuranosyl) cytosine (ECyd), a potent inhibitor of RNA synthesis, was performed using mouse mammary tumor FM3A cells in vitro. Accompanied with the cell death induced by ECyd (3.0 muM) -treatment, about 100-200 kbp-sized and internucleosomal DNA fragmentation were observed by orthogonal-field-alternation gel electrophoresis (OFAGE) and conventional gel electrophoresis, respectively. Protease inhibitors, carbobenzoxy-L-aspart-1-yl[(2,6-dichlorobenzyl)oxy]methane (Z-Asp-CH2-DCB), N alpha-p-tosyl-L-lysine chloromethyl ketone (TLCK) and N-p-tosyl-L-phenylalanine chloromethyl ketone (TPCK), effectively blocked the cell death, suggesting that the proteases inhibited by Z-Asp-CH2-DCB, TLCK or TPCK were involved in the process of cell death.

Stiffness indexes beta of the common carotid and femoral arteries are associated with insulin resistance in NIDDM

OBJECTIVE

To investigate the association between arterial wall stiffness indexes beta of the common carotid artery (CCA) and the femoral artery (FA) and insulin resistance in NIDDM subjects in a cross-sectional study.

RESEARCH DESIGN AND METHODS

We evaluated the arterial stiffness indexes beta of CCA and FA using an ultrasonic phase-locked echo-tracking system in 60 NIDDM subjects attending the diabetes center in Osaka City University Hospital, compared with 120 age- and sex-matched control subjects. Insulin sensitivity indexes were evaluated using a euglycemic-hyperinsulinemic clamp.

RESULTS

Stiffness indexes beta of both CCA and FA were significantly higher in NIDDM subjects than in control subjects (CCA 18.1 +/- 0.9 vs. 11.7 +/- 0.3, respectively, P < 0.001; FA 35.7 +/- 2.3 vs. 23.7 +/- 0.8, respectively, P < 0.001). The mean insulin sensitivity index in NIDDM subjects was 4.69 +/- 0.29 mg.kg-1.min-1.mU-1.l. The stiffness indexes beta of both CCA and FA were inversely correlated with insulin sensitivity indexes (CCA r = -0.393, P = 0.002; FA r = -0.329, P = 0.010), as well as with age, duration of diabetes, and mean blood pressure. In stepwise multiple regression analyses, insulin sensitivity index and duration of diabetes were identified as significant independent variables for stiffness indexes beta in both CCA and FA (CCA R2 = 0.249, P = 0.0003; FA R2 = 0.336, P < 0.001).

CONCLUSIONS

Arterial stiffness indexes beta of CCA and FA were associated with insulin resistance in NIDDM subjects.

Cytotoxic mechanisms of new antitumor nucleoside analogues, 3'-ethynylcytidine (ECyd) and 3'-ethynyluridine (EUrd)

The cytotoxic mechanisms of 1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl)cytosine (ECyd) and 1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl)uracil (EUrd) were studied with mouse mammary tumor FM3A cells and human fibrosarcoma HT1080 cells. ECyd and EUrd are converted to ECyd 5'-triphosphate (ECTP) in the cells. ECTP has also outstanding stability in the cells; the half life of ECTP in FM3A cells was more than 3 days. The metabolisms and mechanisms of these analogues may play a key role in a potent antitumor activities against slow-growing solid tumors.

Rainbow trout Sox24, a novel member of the Sox family, is a transcriptional regulator during oogenesis

We isolated a cDNA clone encoding a novel SRY-type HMG box (Sox) protein, designated Sox24, from a rainbow trout ovary cDNA library. On the basis of the HMG box amino acid sequence, Sox24 can be categorized into the same subgroup of Sox proteins as SOX4, SOX11, and SOX22. The proteins in this group also share a highly conserved sequence at the C-terminus. The Sox24 mRNA is expressed at high levels in the ovary, and in-situ hybridization localized its expression to oocytes. The recombinant protein containing the Sox24 HMG box region bound to an AACAAT sequence strongly in a gel retardation assay. Upon co-transfection into CHO cells, the full-length Sox24 transactivated transcription from a reporter plasmid through the AACAAT binding motif. We used GAL4/Sox24 chimeras with the DNA binding domain of yeast GAL4 at the N-terminus to map the transactivation function to the C-terminal region, which included the conserved sequence. These results suggest that Sox24 plays a role as a transcriptional regulator during oogenesis.

Association of loss of heterozygosity at the p53 locus with chemoresistance in osteosarcomas

Although the osteosarcoma is considered to be among the most chemosensitive malignancies and preoperative chemotherapy is commonly applied, an appreciable proportion of cases are in fact quite sensitive. Predictive markers for chemosensitivity are therefore desirable in order to develop effective treatment strategies. Thirty-two cases of conventional osteosarcomas treated at the Cancer Institute Hospital, Tokyo, were analyzed. The sensitivity to preoperative chemotherapy was investigated with reference to loss of heterozygosity (LOH) at the 17p13 (p53) and 13q14 (Rb) loci and expression of the cell-cycle associated proteins, p53, Rb, p21/Waf-1, mdm-2 and Ki-67, as detected immunohistochemically. LOH was detected by analyzing polymerase chain reaction products at marker microsatellite loci. The efficacy of chemotherapy was evaluated both radiologically and histologically. LOH at p53 or Rb loci was seen in 54% (13/24) and 58% (14/24) of cases, respectively. Only 15% of osteosarcomas with LOH at the p53 locus were sensitive to preoperative chemotherapy, as compared to 64% of tumors without such loss (P < 0.05). A similar but much less distinct tendency was observed with LOH at the Rb locus. No relationship was evident between chemosensitivity and immunohistochemical staining patterns for p53, Rb, p21/Waf-1, mdm-2 or Ki-67. The results suggest that p53 gene deletion, but not the other parameters investigated, may be useful for predicting chemoresistance of osteosarcomas.

cDNA cloning of a novel rainbow trout SRY-type HMG box protein, rtSox23, and its functional analysis

We have isolated a cDNA clone for a new member of Sox genes, termed rtSox23, from a rainbow trout ovary cDNA library. rtSox23 mRNA was notably expressed in ovary and brain. rtSox23 contains a leucine zipper in addition to an SRY-type HMG box. Although the recombinant HMG box region protein of rtSox23 could bind to an AACAAT sequence, the full-length rtSox23 could form a homodimer and did not bind to the sequence. Furthermore, using a two-hybrid system, we have isolated a cDNA clone encoding a protein that bound to the leucine zipper region of rtSox23. This protein was the rainbow trout homologue of mouse nucleoporin p62, which is a component of the nuclear pore complex in nuclear envelope. The rainbow trout p62 mRNA was also prominent in ovary and brain. Taken together, these results suggest that the rainbow trout p62 associates with rtSox23 in vivo and modulates the function of rtSox23.

Depressed mechanoenergetics and compensatory responses in idiopathic dilated cardiomyopathy

The aim of this study was to clarify that the depressed mechanoenergetics in patients with idiopathic dilated cardiomyopathy (DCM) resulted from compensation for the decreased contractility. The study population consisted of eight control subjects, with normal left ventricular size and ejection fraction and 31 patients with DCM. Left ventricular end-systolic elastance (Ees), effective arterial elastance (Ea), external work (EW), and the pressure-volume area (PVA) were measured, using a dual-field volume conductance catheter equipped with a micromanometer-tipped catheter. Ea/Ees was evaluated as ventriculoarterial coupling. Normal hearts worked at almost optimal condition (defined as Ea/Ees = 1/2), while ventriculoarterial coupling was far from the optimum (Ea > Ees) in patients with DCM. Ees in patients with DCM was less than that in control subjects; however, Ea was similar in the two groups. The mismatch of Ea/Ees observed in DCM leads to depressed mechanoenergetics as a result of the compensatory response to maintain adequate blood pressure. Volume enlargement plays an important role in maintaining adequate blood pressure and cardiac output in the course of chronic deterioration of contractility.

cDNA cloning of a new member of the FTZ-F1 subfamily from a rainbow trout

We describe here cDNA cloning of an orphan nuclear receptor family member, tFZR1, which has a FTZ-F1 box. The amino acid sequences of the zinc finger domain and the FTZ-F1 box has 92.8% and 100% identity, respectively, with those of zebrafish FTZ-F1. On the other hand, the overall homology between tFZR1 and zebrafish FTZ-F1 is low (33.0%). The results indicate that tFZR1 is a new member of fushitarazu factor 1 (FTZ-F1) subfamily.

Biochemical and pharmacological profiles of loxiglumide, a novel cholecystokinin-A receptor antagonist

Loxiglumide ((+/-)-4-(3,4-dichlorobenzamido)-N-(3-methoxypropyl)-N- pentylglutaramic acid, CAS 107097-80-3, CR1505) is a new derivative of glutaramic acid. Radioligand displacement assay was performed to characterize the selectivity of loxiglumide to CCK-A (cholecystokinin-A) receptor (rat pancreas and bovine gallbladder) and CCK-B/gastrin receptors (guinea pig cerebral cortex and guinea pig gastric parietal cell). And tissue bioassay was performed to investigate the effect of the compound on contractions of the guinea pig gallbladder and ileum. Loxiglumide inhibited 125I-CCK-8 binding to rat pancreatic and bovine gallbladder membranes with IC50 values of 195 and 77.1 nmol/l, respectively. Loxiglumide also inhibited 125I-CCK-8 binding to guinea pig cerebral cortex membranes and parietal cells with IC50 values of 12363 and 15455 nmol/l, respectively. In addition, loxiglumide inhibited 125I-gastrin binding to guinea pig parietal cells with IC50 values of 6134 nmol/l. These results indicate that the affinity of loxiglumide to CCK-A receptor is at least 63 times greater than that to CCK-B/gastrin receptors. In vitro functional studies utilizing CCK-induced contractions of the isolated guinea pig gallbladder and ileum further demonstrate that loxiglumide acts as a competitive CCK antagonist with a high affinity to these tissues (gallbladder, pA2:6.71).

Development of systemic lupus erythematosus in a rheumatoid arthritis patient with anti-ribosomal P protein antibody

We describe a patient with rheumatoid arthritis (RA) whose sera contained a high titre of an antibody targeting cytoplasmic ribosomal P proteins (anti-P). This association preceded by 6 years the development of serological and clinical manifestations of systemic lupus erythematosus (SLE). The clinical significance of anti-P for the diagnosis of SLE is discussed.

Cardiotoxicity of a new anthracycline derivative (SM-5887) following intravenous administration to rabbits: comparative study with doxorubicin

The degree of cardiotoxicity of SM-5887 compared with that of doxorubicin was investigated in rabbits. Two experimental groups were administered high and low doses of SM-5887, respectively. One group was administered doxorubicin and another group was administered the vehicle only were prepared as positive and negative controls, respectively. Drugs were intravenously administered 3 times a week for 8 weeks. At terminus, electrocardiograms were recorded under anesthesia. The blood was collected for haematology and blood biochemistry analyses. Myocardial tissue damage was evaluated using light and electron microscopy. In the electrocardiogram study, prolongation of QTc interval and ST-T change were observed in rabbits administered SM-5887 and doxorubicin. Morphological studies showed that myocardial tissue damage in animals administered SM-5887 was comparable to that in the negative controls, and less than that observed in the positive controls. The general toxicological investigations uniformly indicated lower toxicity in the SM-5887 group than in the doxorubicin group at equivalent dosages. In total, considering the results of antitumor efficacy studies comparing SM-5887 with doxorubicin, these results indicate that the cardiotoxicity of SM-5887 is very slight, and that the general toxicity of SM-5887 is lower than that of doxorubicin.

Rainbow trout SOX9: cDNA cloning, gene structure and expression

We have isolated and characterized rainbow trout SOX9 cDNA and genomic clones. The cDNA encodes a protein of 488 amino acids (aa) with an HMG box and has 70% aa sequence identity with human SOX9. The rainbow trout and human SOX9 genes show a similar gene structure, and the two introns in the coding region are located at conserved positions. In rainbow trout, the SOX9 mRNA was prominent in testis and brain.

Ligation of the T cell antigen receptor induces tyrosine phosphorylation of p105CasL, a member of the p130Cas-related docking protein family, and its subsequent binding to the Src homology 2 domain of c-Crk

p105CasL (CasL) is a recently identified signaling molecule closely related to the p130Cas (Crk-associated substrate) docking protein. CasL has a single Src homology (SH) 3 domain in its N-terminal portion followed by multiple consensus motifs for binding to SH2 domains. Like original p130Cas, CasL undergoes tyrosine phosphorylation upon integrin-mediated cell adhesion. In the present report, we provide direct evidence that CasL is also involved in T cell antigen receptor (TcR)-mediated signal transduction. In binding studies in vitro using glutathione-S-transferase fusion proteins, we have identified 105- and 120-kDa phosphotyrosyl proteins (pp105 and pp120, respectively) tightly bound to the SH2 domain of the Crk adapter protein in the H9 human T cell line after stimulation through the CD3/TcR complex. pp120, but not pp105, also bound to the SH3 of another adapter protein, Ash/Grb2. Immunoblotting with specific antibodies revealed that pp120 and pp105 were identical to the c-cbl proto-oncogene product (p120cbl) and CasL, respectively. Association between Crk and tyrosine-phosphorylated CasL after TcR stimulation was also confirmed in vivo. CasL phosphorylation induced by TcR ligation reached maximal levels within 2 min and rapidly declined thereafter, whereas the integrin-dependent response occurred slowly and was more prolonged. Finally, we demonstrated that Crk/CasL association occurred in peripheral blood T lymphocytes in response to TcR engagement. Our findings suggest that CasL is involved in T cell activation signals and resides at a point where two distinct receptor-mediated signaling pathways converge. This provides one mechanism by which integrins may mediate T cell co-stimulation.