Phase I study of the pharmacokinetics of a radioimmunoconjugate, 90Y-T101, in patients with CD5-expressing leukemia and lymphoma

Ten patients with advanced or refractory CD5-expressing hematologic neoplasms [two with chronic lymphocytic leukemia and eight with cutaneous T-cell lymphoma (CTCL)] were treated in a Phase I study with the radioimmunoconjugate 90Y-T101, which targets CD5+ lymphocytes. Prior imaging studies using 111In-T101 demonstrated uptake in involved lymph nodes and skin in patients with CTCL, and Phase I studies with unmodified T101 demonstrated transient responses. In this study, patients were treated with 5 or 10 mCi of 90Y chelated to T101 via isothiocyanatobenzyl diethylenetriamine pentaacetic acid, along with tracer doses of 111In-T101 for imaging. The biodistribution of the radioimmunoconjugate was determined by measuring 90Y and 111In blood clearance, urine excretion, and accumulation in bone marrow and in involved skin lesions. The intravascular pharmacokinetics of 90Y were predicted by 111In-labeled T101. The greatest differences in biodistribution between 111In and 90Y were in the higher bone accumulation of 90Y and its lower urinary excretion. Imaging studies demonstrated targeting of skin lesions and involved lymph nodes in CTCL patients. The predominant toxicity was bone marrow suppression. Rapid antigenic modulation of CD5 on circulating T and B cells was observed. Recovery of T-cell populations occurred within 2-3 weeks; however, suppression of B-cell populations persisted after 5+ weeks. All CTCL patients developed human antimouse antibody after one cycle and thus were not retreated; one patient with chronic lymphocytic leukemia received a second cycle of therapy. Partial responses occurred in five patients, two with chronic lymphocytic leukemia and three with CTCL. The median response duration was 23 weeks. One CTCL patient who subsequently received electron beam irradiation to a residual lesion is disease-free after 6 years.     

Important immunoregulatory role of interleukin-11 in the inflammatory process in rheumatoid arthritis

OBJECTIVE: To investigate the possible immunoregulatory role of interleukin-11 (IL-11) in rheumatoid arthritis (RA). METHODS: IL-11 protein was assayed in RA tissue, and the effect of exogenous IL-11 on neutralization of endogenous IL-11 was investigated with respect to tumor necrosis factor alpha (TNFalpha), matrix metalloproteinase (MMP), and tissue inhibitor of metalloproteinases (TIMP) production. RESULTS: IL-11 was found in RA synovial membranes, synovial fluids, and blood sera. Blockade of endogenous IL-11 resulted in a 2-fold increase in TNFalpha levels, which increased to 22-fold if endogenous IL-10 was also blocked. Addition of exogenous IL-11 inhibited spontaneous TNFalpha production in RA synovium only in the presence of soluble IL-11 receptor. However, exogenous IL-11 directly inhibited spontaneous MMP-1 and MMP-3 production, and up-regulated TIMP-1 in RA synovial tissue. CONCLUSION: IL-11 has important endogenous immunoregulatory effects in RA synovium, which suggests that exogenous IL-11 may have therapeutic activity in RA.     

Initiating genetic events in small renal neoplasms detected by comparative genomic hybridization

PURPOSE: To identify the genetic alterations associated with renal adenomas. MATERIALS AND METHODS: We analyzed 37 renal adenomas obtained at autopsy (23 papillary and 14 non-papillary) by comparative genomic hybridization. RESULTS: In papillary tumors, the median number of gains and losses of genetic material per tumor was 2.0 and 1.0, respectively. Papillary tumors were characterized predominantly by gains of genetic material on chromosomes 7 (57%), 17 (35%), 16 (26%), 12 (26%), 3 (22%), 20 (22%) and loss of a sex chromosome (83%). In 6 papillary tumors less than or equal to 5 mm. in diameter, gain of chromosome 7 occurred in 4 specimens. Initiating events for papillary renal adenomas include gain of chromosome 7 and loss of a sex chromosome. In non-papillary tumors, the median number of gains and losses of genetic material per tumor was 1.0 and 1.0, respectively. Non-papillary tumors were characterized by loss of genetic material on chromosome 3p (50%), loss of a sex chromosome (36%) and a gain of chromosome 5 (43%). The initiating event for non-papillary renal adenomas is the loss of chromosome 3p. CONCLUSIONS: Renal adenomas demonstrate similar genetic alterations as clinically detected renal cell carcinomas. Their clinically indolent course may, in part, be a result of the lower number of genetic alterations per tumor than their clinically detected counterparts. Renal adenomas are thus small carcinomas which have not yet acquired the necessary genetic alterations leading to tumor progression.     

The effects of adenine dinucleotides on epileptiform activity in the CA3 region of rat hippocampal slices

Alpha, omega-adenine dinucleotides (Ap(n)A) consist of two adenosine molecules linked at the 5' position by phosphate groups, the number of which is denoted by n and can range from 2 to 6. The aim of this study was to investigate the effect of Ap4A and Ap5A on the rate of epileptiform activity. Hippocampal slices (450 microm), when perfused with a medium containing no added magnesium and 4-aminopyridine (50 microM), generate epileptiform activity of an interictal nature. Ap4A and Ap5A at 1 microM depressed the discharge rate to a significant extent. At this concentration adenosine (1 microM) did not produce any effect. However at 10 microM adenosine, Ap4A and Ap5A all decreased the burst frequency. Adenosine deaminase (0.2 U/ml) totally annulled the inhibition of epileptiform activity produced by 10 microM adenosine or 1 microM Ap4A and Ap5A. Adenosine deaminase did not significantly change the maximum depression of activity produced by 10 microM Ap4A and Ap5A. 8-cyclopentyl-1,3-dimethylxanthine, an A1, receptor antagonist, increased the basal rate of epileptiform activity and prevented the depression of burst discharges by Ap4A. 5'-adenylic acid deaminase converts AMP into IMP which is inactive. 5'-adenylic acid deaminase did not prevent the inhibitory effects of Ap4A. The results suggests that in the CA3 region of the hippocampus, Ap4A and Ap5A act partly by stimulating xanthine-sensitive receptors directly and partly through the formation of the metabolite, adenosine.     

Possible role of decorin glycosaminoglycans in fibril to fibril force transfer in relative mature tendons--a computational study from molecular to microstructural level

Experimental studies on immature tendons have shown that the collagen fibril net is discontinuous. Manifold evidences, despite not being conclusive, indicate that mature tissue is discontinuous as well. According to composite theory, there is no requirement that the fibrils should extend from one end of the tissue to the other; indeed, an interfibrillar matrix with a low elastic modulus would be sufficient to guarantee the mechanical properties of the tendon. Possible mechanisms for the stress-transfer involve the interfibrillar proteoglycans and can be related to the matrix shear stress and to electrostatic non-covalent forces. Recent studies have shown that the glycosaminoglycans (GAGs) bound to decorin act like bridges between contiguous fibrils connecting adjacent fibril every 64-68 nm; this architecture would suggest their possible role in providing the mechanical integrity of the tendon structure. The present paper investigates the ability of decorin GAGs to transfer forces between adjacent fibrils. In order to test this hypothesis the stiffness of chondroitin-6-sulphate, a typical GAG associated to decorin, has been evaluated through the molecular mechanics approach. The obtained GAG stiffness is piecewise linear with an initial plateau at low strains (<800%) and a high stiffness region (3.1 x 10(-11)N/nm) afterwards. By introducing the calculated GAG stiffness in a multi-fibril model, miming the relative mature tendon architecture, the stress-strain behaviour of the collagen fibre was determined. The fibre incremental elastic modulus obtained ranges between 100 and 475 MPa for strains between 2% and 6%. The elastic modulus value depends directly on the fibril length, diameter and inversely on the interfibrillar distance. In particular, according to the obtained results, the length of the fibril is likely to play the major role in determining stiffness in mature tendons.     

The effect of gentamicin on acetylsalicylic acid-induced platelet antiaggregatory action in mouse pial arterioles

Proton nuclear magnetic resonance (1H-NMR) spectroscopy is used to identify a preferred binding site for uncharged hydrophilic polymers on the surface of hen egg-white lysozyme. Chemical shift titrations show that exchangeable proton signals from amino acids Arg-61, Trp-62, Trp-63, Arg-73, Lys-96 and Asp-101 are selectively perturbed upon binding of poly(ethylene oxide), poly(ethylene glycol) and poly(ethylene-co-propylene oxide). The greatest binding-induced chemical shift changes are observed for Trp-62, Arg-61 and Arg-73 at the edge of the active site cleft of the protein, consistent with a predominantly hydrophobic interaction mode involving the polymer ethylene moieties. The more hydrophilic species poly(dihydroxypropyl methacrylate) causes similar but substantially smaller chemical shift effects than the other polymers, confirming the nature of the interaction. A dissociation constant of 76+/-5 mM is determined for the poly(ethylene glycol)-lysozyme complex. The relatively low affinity of the protein-polymer interactions compared to oligosaccharide substrate binding suggests that lysozyme activity is minimally affected by these materials.     

Insulin-like growth factor (IGF)-I but not IGF-II promotes lean growth and feed efficiency in broiler chickens

The efficacy of exogenous IGFs to stimulate growth and modulate protein and fat deposition was examined in a number of broiler chicken lines. From around 600 g body weight the chickens received a continuous infusion of vehicle (0.1 M acetic acid), human recombinant IGF-I or [Gly1]IGF-II at 300 microg/kg body weight per day, or a combined infusion of 150 microg/kg/day of each IGF for 2 weeks. Experiment 1 used commercial broiler female chickens and included measurements of nitrogen balance, Ntau-methylhistidine excretion and muscle protein synthesis rates. In Experiment 2 the same treatments were applied to three experimental lines of chickens selected for high food consumption (relatively fat), high food utilisation efficiency (relatively lean), or at random (control). IGF-I, but not IGF-II, significantly increased growth rate and food utilisation efficiency by around 10-15% in each experiment, an effect which was consistent across all genotypes. Nitrogen balance was significantly increased by IGF-I in Experiment 1 as was carcass nitrogen content in Experiment 2, indicating that the increased growth was in lean tissue. Carcass fat was consistently reduced in chickens receiving IGF-I and was related to the levels of circulating IGF-I (r2 = 0.30, P < 0.01) but not triiodothyronine. Protein synthesis rates were unaffected by treatment and could not account for increased growth rate. However, there was a significant reduction in Ntau-methylhistidine excretion indicating a reduced rate of muscle protein breakdown in IGF-I-treated chickens (1. 56%/day vs 2.05%/day for IGF-I-treated vs controls, P < 0.05). The efficiency of feed utilisation was inversely related to the rate of protein breakdown (r2 = 0.25, P < 0.01). In conclusion, these experiments are the first to report an enhancement of growth and food utilisation efficiency by broiler chickens receiving exogenous IGF-I. Our results show that IGF-I may be important in controlling the growth and efficiency of food utilisation of young chickens at least in part by modulating the rates of protein breakdown.     

Dietary beta-adrenoceptor agonists have a persistent effect on nitric oxide synthesis in rat cultured smooth muscle cells

Several compounds including lipopolysaccharide and sympathomimetics stimulate the expression of the inducible nitric oxide synthase in vascular smooth muscle cells. We evaluated the effect of clenbuterol on nitric oxide (NO) production by vascular smooth muscle cells of the rat aorta in culture. Wistar rats were divided into three diet groups (control, clenbuterol and washout). Aortic vascular smooth muscle cells from rats from these 3 diet groups were cultured in the presence and absence of lipopolysaccharide and/or beta-adrenoceptor agonists. NO release was measured by Griess reagent. Clenbuterol or salbutamol added to cells from control rats potentiated lipopolysaccharide-induced NO release. Cells from rats fed on clenbuterol, in a medium without beta-adrenoceptor agonists, showed a similar potentiation, even after a 10-day washout period. The addition of beta-adrenoceptor agonists to the latter cells did not increase NO production. NG-Nitro-L-arginine decreased nitrite production in lipopolysaccharide-stimulated cells. Our results demonstrate that dietary clenbuterol has a persistent 'ex vivo' effect on lipopolysaccharide-induced NO production by cultured vascular smooth muscle cells.     

4-(3'-Bromo-4'hydroxylphenyl)-amino-6,7-dimethoxyquinazoline: a novel quinazoline derivative with potent cytotoxic activity against human glioblastoma cells

The novel quinazoline derivative 4-(3'-bromo-4'-hydroxylphenyl)-amino-6,7-dimethoxyquinazoline (WHI-P154) exhibited significant cytotoxicity against U373 and U87 human glioblastoma cell lines, causing apoptotic cell death at micromolar concentrations. The in vitro antiglioblastoma activity of WHI-P154 was amplified > 200-fold and rendered selective by conjugation to recombinant human epidermal growth factor (EGF). The EGF-P154 conjugate was able to bind to and enter target glioblastoma cells within 10-30 min via receptor (R)-mediated endocytosis by inducing internalization of the EGF-R molecules. In vitro treatment with EGF-P154 resulted in killing of glioblastoma cells at nanomolar concentrations with an IC50 of 813 +/- 139 nM, whereas no cytotoxicity against EGF-R-negative leukemia cells was observed, even at concentrations as high as 100 microM. The in vivo administration of EGF-P154 resulted in delayed tumor progression and improved tumor-free survival in a severe combined immunodeficient mouse glioblastoma xenograft model. Whereas none of the control mice remained alive tumor-free beyond 33 days (median tumor-free survival, 19 days) and all control mice had tumors that rapidly progressed to reach an average size of > 500 mm3 by 58 days, 40% of mice treated for 10 consecutive days with 1 mg/kg/day EGF-P154 remained alive and free of detectable tumors for more than 58 days with a median tumor-free survival of 40 days. The tumors developing in the remaining 60% of the mice never reached a size > 50 mm3. Thus, targeting WHI-P154 to the EGF-R may be useful in the treatment of glioblastoma multiforme.     

Allosteric dominance in carbamoyl phosphate synthetase

A linked-function analysis of the allosteric responsiveness of carbamoyl phosphate synthetase (CPS) from E. coli was performed by following the ATP synthesis reaction at low carbamoyl phosphate concentration. All three allosteric ligands, ornithine, UMP, and IMP, act by modifying the affinity of CPS for the substrate MgADP. Individually ornithine strongly promotes, and UMP strongly antagonizes, the binding of MgADP. IMP causes only a slight inhibition at 25 degreesC. When both ornithine and UMP were varied, models which presume a mutually exclusive binding relationship between these ligands do not fit the data as well as does one which allows both ligands (and substrate) to bind simultaneously. The same result was obtained with ornithine and IMP. By contrast, the actions of UMP and IMP together must be explained with a competitive model, consistent with previous reports that UMP and IMP bind to the same site. When ornithine is bound to the enzyme, its activation dominates the effects when either UMP or IMP is also bound. The relationship of this observation to the structure of CPS is discussed.