Metabolically based treatment of stunned myocardium

Reversible myocardial ischemia is associated with a rapid decrease in contractility and prolonged postischemic ventricular dysfunction, due in part to altered intracellular calcium handling and/or contractile protein dysfunction. The maintenance of intracellular calcium homeostasis and force development by the contractile apparatus are dependent upon the free energy derived from ATP hydrolysis. This energy of hydrolysis is determined by the myocardial phosphorylation potential, an estimate of which can be made from the ratio (CrP)/(Cr) x (P(i)). Results from in vitro and in vivo studies suggest that pyruvate enhances contractility in both normal and stunned myocardium by enhancing myocardial phosphorylation potential. In regionally stunned porcine myocardium, pyruvate infusion increased recovery of regional ventricular function from 33% +/- 4% of preischemic systolic wall thickening to 81% +/- 4% and increased the (CrP)/(Cr) x (P(i)) ratio fivefold from 0.21 +/- 0.04 to 1.05 +/- 0.08. Thus, metabolic substrates that enhance myocardial energetics and ventricular function may be effective agents for attenuating postischemic ventricular function.

Delayed rectifier potassium current (IK) in latent atrial pacemaker cells isolated from cat right atrium

Whole-cell recording techniques were used to study the delayed rectifier K+ current (IK) in latent pacemaker cells isolated from cat right atrium. From a holding potential of -40 mV, depolarizing clamp steps elicited L-type Ca2+ current followed by an increasing outward current (IK). The time course of tail current amplitudes paralleled that of the time-dependent activation of outward current. Activation of IK exhibited a sigmoidal time course that was best fit by a power function where the activation variable was raised to the second power. The voltage-dependence of IK activation exhibited a sigmoidal relationship between -40 and +30 mV. The half-maximal activation voltage and slope factor were -21.9 +/- 1.3 and 13.8 +/- 0.9 mV respectively (n = 6). The fully activated I/V relationship of IK was linear between -100 and -30 mV and inwardly rectified at more positive voltages. Following IK activation, hyperpolarizations more negative than about -50 mV elicited tail currents that consisted of both IK deactivation and I(f) activation. A subtraction protocol was used to isolate IK tail currents. In 5.4 mM extracellular [K+], IK tail currents exhibited a reversal potential of -78.2 +/- 0.3 mV (n = 6). The reversal potential of IK was linearly related to log extracellular [K] and the slope was 51.5 mV per ten-fold change in extracellular [K]. At -70 mV, IK tail currents decayed as a single exponential function with a time constant of 159 +/- 16 ms (n = 6). These results indicate that latent atrial pacemakers exhibit IK activated by depolarization.(ABSTRACT TRUNCATED AT 250 WORDS)

4-1BB T-cell antigen binds to mature B cells and macrophages, and costimulates anti-mu-primed splenic B cells

4-1BB is expressed on activated murine T cells and may function as an accessory signaling molecule during T-cell activation. To identify putative 4-1BB ligands, a fusion protein consisting of the extracellular domain of 4-1BB fused to human placental alkaline phosphatase (4-1BB-AP) was constructed. Alkaline phosphatase activity could then be used as an indicator of the relative amount of bound 4-1BB. These studies indicated that 4-1BB-AP specifically bound to the surface of various mature B and macrophage cell lines. 4-1BB-AP bound at low levels to T cell lines (non-activated and anti-CD3-activated), pre-B-cell lines, and an immature macrophage cell line. 4-1BB-AP did not bind to a glial tumor cell line, HeLa cells, or COS cells. In addition, 4-1BB-AP bound at higher levels to F(ab')2 anti-mu-activated primary B cells compared to anti-CD3-activated primary T cells. Scatchard analysis indicated that the A20 B cell lymphoma expressed 3680 binding sites per cell with a Kd of 1.86 nM. Affinity cross-linking studies demonstrated that a major cell surface species of 120 kDa bound to 4-1BB-AP; 4-1BB-AP also bound to a minor species of approximately 60 kDa. The addition of paraformaldehyde-fixed SF21 cells expressing recombinant 4-1BB synergized with F(ab')2 anti-mu in inducing splenic B cell proliferation suggesting that 4-1BB may function as a regulator of B cell growth.

Convergence of quantum electrodynamics in a curved modification of Minkowski space

The interaction and total hamiltonians for quantum electrodynamics, in the interaction representation, are entirely regular self-adjoint operators in Hilbert space, in the universal covering manifold M of the conformal compactification of Minkowski space Mo. (M is conformally equivalent to the Einstein universe E, in which Mo may be canonically imbedded.) In a fixed Lorentz frame this may be expressed as convergence in a spherical space with suitable periodic boundary conditions in time. The traditional relativistic theory is the formal limit of the present variant as the space curvature vanishes.

In vitro femoral arterial responses to vasoconstrictor and vasodilator agents in endotoxin shock

The hypothesis for this study is that the decreased arterial response to catecholamines may be due to the effect of endotoxemia on vessel tone. One control ring was taken from one femoral artery of a Wistar rat and after endotoxin (ENDT) infusion (i.v. 6 mg/kg-1 hr.), one ring was removed from the contralateral artery. The post-ENDT rings were tested in four groups which were determined by the mean arterial pressure (MAP) levels at the time of dissection: 100 mmHg (120 min), 80 mmHg (270 min), 60 mmHg (300 min) or 40 mmHg (330 min). KCl, phenylephrine (PHE) and arginine-vasopressin (AVP) dose-response curves (DR) were obtained at a preload of 500 mg which allowed the maximum response in control rings. When compared at 500 mg preload the maximal active response to all agonists post-ENDT was decreased by about 50%. By increasing the preload on the ENDT rings to 800 mg, the active tension became 2.49 times the active tension of the control rings. Length-tension experiments also showed a greater response for post-ENDT rings and a greater preload at maximum response but the ring circumference was the same. In contrast the in vivo femoral artery diameters at 90 min post-ENDT (100 mmHg) were 82.6% of control. Endothelium-dependent relaxation by acetylcholine (ACh) was abolished by ENDT but endothelium-independent relaxation to nitroprusside (NP) was not affected. It is concluded that the resting tone and active tension of femoral artery smooth muscle is increased by ENDT and the decreased in vivo responsiveness to vasoconstrictor agonists may be the result of vessel constriction due to loss of endothelium. The results also suggest that in vitro comparison of vessels in studies of endotoxin shock be done at the same muscle length rather than at the same preload.

Fast gradient-based methods for Bayesian reconstruction of transmission and emission PET images

The authors describe conjugate gradient algorithms for reconstruction of transmission and emission PET images. The reconstructions are based on a Bayesian formulation, where the data are modeled as a collection of independent Poisson random variables and the image is modeled using a Markov random field. A conjugate gradient algorithm is used to compute a maximum a posteriori (MAP) estimate of the image by maximizing over the posterior density. To ensure nonnegativity of the solution, a penalty function is used to convert the problem to one of unconstrained optimization. Preconditioners are used to enhance convergence rates. These methods generally achieve effective convergence in 15-25 iterations. Reconstructions are presented of an (18)FDG whole body scan from data collected using a Siemens/CTI ECAT931 whole body system. These results indicate significant improvements in emission image quality using the Bayesian approach, in comparison to filtered backprojection, particularly when reprojections of the MAP transmission image are used in place of the standard attenuation correction factors.

[Quantitative determination of rhapontin in root of Rheum hotaoense by TLC-scanning]

The contents of rhapontin in the root of Rheum hotaoense were determined by CS-920 TLC-scanning of silica gel plate A mixture of benzene-EtOAc-EtOH (5 : 3, 5 : 1.5) was used as the developing solvent. Recovery was 100.44%, RSD 3.0%.

DUN1 encodes a protein kinase that controls the DNA damage response in yeast

DNA damage induces the expression of many genes proposed to enhance DNA repair capacities. We investigated the mechanism by which DNA damage induces transcription of RNR3, a subunit of ribonucleotide reductase. Five complementation groups of DNA-damage uninducible (dun) mutants were identified. Each is sensitive to DNA damage. dun1 mutants are also defective for RNR1 and RNR2 induction but are proficient for induction of other genes, defining the existence of at least two distinct DNA damage induction pathways. DUN1 encodes a nuclear protein kinase that is also a phosphoprotein. Phosphorylation of Dun1 increases in response to DNA damage in a Dun1-dependent manner, suggesting an increase in autophosphorylation activity. These results establish the existence of a eukaryotic SOS response regulated by protein phosphorylation.

[A study of CGRP receptor and its effect on the growth of human pancreatic carcinoma cells]

In the present studies the calcitonin gene-related peptide (CGRP) receptors were characterized by radioligand analysis and the effect of CGRP and CGRP receptor antagonist on the growth of human pancreatic carcinoma cells (PU-PAN-1) was determined by 3H-TdR incorporation assay. The results indicated that human pancreatic carcinoma cells possess distinct CGRP receptors. CGRP stimulated the growth of PU-PAN-1 tumor cells, and CGRP receptor antagonist CGRP8-37 inhibited these effects. These results suggests that CGRP receptors may play an important role in the growth of human pancreatic carcinoma cells (PU-PAN-1).

Calcium permeability of nicotinic acetylcholine receptor channels in bovine adrenal chromaffin cells

The fractional contribution of Ca to current flow through neuronal-type nicotinic acetylcholine receptor channels was determined by quantitative fluorescence microfluorimetry using fura-2. The method, which has been applied already to several types of cells and channels is described in detail here. At -70 mV and 2 mM external Ca concentration it was found that Ca contributes 2.5% to the net current. The fractional contribution was found to be voltage dependent, increasing at negative potentials e-fold for a 110 mV potential difference. Total non-specific cation current was found to have a bell-shaped dependence on external Ca concentration peaking at 2 mM.

[Detection of the direct genotyping of HSV by PCR and its primal usage in ophthalmology]

The direct genotyping of Herpes Simplex Virus (HSV) by polymerase chain reaction (PCR) was used to analysis the smears from corneas or tears of 37 cases suspected HSK. The results show that PCR is a sensitive rapid and simple method. The key procedure is taking specimens.

Expression of gap junction connexin 43 and connexin 43 mRNA in different regional tissues of intestine in dog

To determine the distribution of gap junction protein connexin 43 (Cx43) and the expression of Cx43 mRNA in different regions of canine small intestine and colon, modified Western blot and Northern blot techniques were used with a site-directed antibody raised against a synthetic peptide of Cx43 Anti-Cx43 (252-271) and a probe of 1.3-kb Cx43 cDNA. Equal amounts of plasma membrane enriched fraction (10 micrograms protein) from small intestinal and colonic circular muscle, longitudinal muscle, and colonic submucous plexus border of circular muscle (interstitial cells of Cajal rich layer, ICC) of the dog were resolved by 12% sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transferred onto nitrocellulose, and blotted by chemiluminescent assay. Different yet characteristic ratios of the immunoreactive gap junction proteins located at 43 and 40 kDa were found in membranes from small intestinal and colonic circular smooth muscle, and ICC. These results suggest that gap junction Cx43 in dog heart, dog small intestinal and colonic circular muscle, and ICC is homologous to rat heart. Furthermore, with the use of Northern blot hybridization with a 1.3-kb Cx43 cDNA, a 3.0-kb message was observed in small intestinal and colonic circular muscles, longitudinal muscles, and ICC. However, the mRNA signal of small intestinal circular muscle was the strongest and that of longitudinal muscle was weakest, especially from colon longitudinal muscle.(ABSTRACT TRUNCATED AT 250 WORDS)

Macrophage inflammatory protein-1 alpha rapidly modulates its receptors and inhibits the anti-CD3 mAb-mediated proliferation of T lymphocytes

Macrophage inflammatory protein-1 alpha (MIP-1 alpha) is a member of the intercrine/chemokine family which consists of basic, heparin-binding, small molecular weight proteins. We have previously shown that a T cell line, CTLL-R8, carried high-affinity receptors for MIP-1 alpha and the proliferation of CTLL-R8 cells was inhibited by murine recombinant (mr) MIP-1 alpha. We extended our previous studies to murine resting splenic T lymphocytes to determine whether the inhibition of T cell proliferation is a general property of MIP-1 alpha. The resting splenic T cells carried approximately 680 high-affinity binding sites for mrMIP-1 alpha; more than 90% of the primary T cells carried MIP-1 alpha receptors. When the T cells were stimulated with immobilized anti-CD3 mAb in the presence of accessory cells, the MIP-1 alpha binding was reduced. The lowest binding was obtained 2 h after anti-CD3 mAb stimulation due to the internalization of MIP-1 alpha receptors. mrMIP-1 alpha inhibited the anti-CD3 mAb-mediated proliferation of murine splenic T lymphocytes. The maximum inhibition was obtained when mrMIP-1 alpha was added 30 min before anti-CD3 mAb stimulation. Slight inhibition of T cell proliferation was observed when mrMIP-1 alpha was added at the same time as anti-CD3 mAb stimulation. These results indicate that T lymphocytes are regulated negatively by MIP-1 alpha, which occurs when the T cells are exposed to MIP-1 alpha before activation. The negative effect of MIP-1 alpha seems to be mediated in part by the inhibition of IL-2 production, for there was a reduction in both the IL-2 mRNA levels and the IL-2 activity in supernatants from T cells preincubated with MIP-1 alpha before anti-CD3 mAb stimulation.

Macrophage inflammatory protein-1 alpha rapidly modulates its receptors and inhibits the anti-CD3 mAb-mediated proliferation of T lymphocytes

Macrophage inflammatory protein-1 alpha (MIP-1 alpha) is a member of the intercrine/chemokine family which consists of basic, heparin-binding, small molecular weight proteins. We have previously shown that a T cell line, CTLL-R8, carried high-affinity receptors for MIP-1 alpha and the proliferation of CTLL-R8 cells was inhibited by murine recombinant (mr) MIP-1 alpha. We extended our previous studies to murine resting splenic T lymphocytes to determine whether the inhibition of T cell proliferation is a general property of MIP-1 alpha. The resting splenic T cells carried approximately 680 high-affinity binding sites for mrMIP-1 alpha; more than 90% of the primary T cells carried MIP-1 alpha receptors. When the T cells were stimulated with immobilized anti-CD3 mAb in the presence of accessory cells, the MIP-1 alpha binding was reduced. The lowest binding was obtained 2 h after anti-CD3 mAb stimulation due to the internalization of MIP-1 alpha receptors. mrMIP-1 alpha inhibited the anti-CD3 mAb-mediated proliferation of murine splenic T lymphocytes. The maximum inhibition was obtained when mrMIP-1 alpha was added 30 min before anti-CD3 mAb stimulation. Slight inhibition of T cell proliferation was observed when mrMIP-1 alpha was added at the same time as anti-CD3 mAb stimulation. These results indicate that T lymphocytes are regulated negatively by MIP-1 alpha, which occurs when the T cells are exposed to MIP-1 alpha before activation. The negative effect of MIP-1 alpha seems to be mediated in part by the inhibition of IL-2 production, for there was a reduction in both the IL-2 mRNA levels and the IL-2 activity in supernatants from T cells preincubated with MIP-1 alpha before anti-CD3 mAb stimulation.

Effect of muscle length on the in vitro comparison of femoral arteries before and after endotoxin shock

Control and endotoxin-treated femoral arteries were compared in vitro for the effect of muscle length. Rats were anesthetized with pentobarbital, and endotoxin (6 mg/kg) was infused for 1 h. A control ring before endotoxin treatment and a ring after endotoxin treatment (blood pressure = 40 mmHg) were excised from the contralateral artery for length-tension and dose-response experiments with phenylephrine. The initial length for resting tension (Li) was shorter for endotoxic rings (1.23 +/- 0.01 vs. 1.41 +/- 0.02 mm in control), but the length of maximum active tension (Lmax) was the same. In length-tension experiments the values for active tension (6.36 +/- 0.61 vs. 4.06 +/- 0.60 x 10(3) dyn/cm), preload at Lmax (1,333 +/- 204 vs. 733 +/- 146 mg), and passive stiffness were increased after endotoxin. In dose-response experiments at the same preload, the endotoxic rings had a lower active tension (3.28 +/- 0.28 vs. 6.55 +/- 0.27 x 10(3) dyn/cm) but the same sensitivity. At Lmax, active tension (12.45 +/- 0.48 vs. 5.01 +/- 0.89 x 10(3) dyn/cm in control vessels) and sensitivity (half-maximum effective dose = 0.68 +/- 0.8 x 10(-6) vs. 1.39 +/- 0.29 x 10(-6) M in control vessels) were greater for endotoxic rings. These experiments show that phenylephrine sensitivity and active tension in the rat femoral artery are increased by endotoxin shock, and the importance of muscle length is implied.

Characterization of minisatellite sequences from Oryza sativa

Two DNA sequences were cloned from the genome of cultivated rice (Oryza sativa L.) by cross-hybridization with the human minisatellite sequence 33.6. The rice sequences consisted of tandem direct repeats, which showed significant similarity to the 33.6 consensus sequence. Profiles capable of distinguishing different rice cultivars were detected by cross-hybridization with a DNA probe amplified by the polymerase chain reaction from one of the rice minisatellite sequences.

Differences in arterial and arteriolar endothelial structure during endotoxin shock

Previous studies of physiological and ultrastructural assessment changes in the walls of the femoral artery and A1, A2, and A3 arterioles in the rat cremaster muscle after infusion of Escherichia coli endotoxin (ENDT) (6 mg/kg-1 hr. period) indicate there may be a difference in the alteration of the endothelial structure of arteries and arterioles. Functionally, ENDT has been shown to abolish acetylcholine (ACh)-induced relaxation in the femoral artery [Zhou, PhD dissertation, University of South Florida, Tampa, 1992]. Dilations of A1 arterioles were shown to be reduced, but dilations of A2 and A3 arterioles were not significantly changed from control [Baker and Sutton, Am J Physiol, 264:H 1118-H 1123, 1993]. In the current study, ultrastructural evaluation of femoral arterial tissue post-ENDT at the mean arterial pressure (MAP) of 100 mm Hg revealed partially destroyed endothelial cells. The MAP decreased as the animal progressed into shock. At 80 mm Hg, 60 mm Hg and 40 mm Hg, essentially all endothelial cells were destroyed, with the internal elastic lamina denuded. In contrast, endotoxin damage in the A1, A2, and A3 arterioles was minimal even at a MAP of 40 mm Hg. Endothelial cells of A1 arterioles post-ENDT had more vacuoles than at control. Therefore, arteriolar endothelium was functionally and anatomically relatively undamaged, consequent to endotoxin administration, in contrast to femoral arteries where the endothelium was destroyed in a short time.

[Extraction and homogeny of larvicidal toxin in Bacillus sphaericus strain C3-41]

Spore-crystal toxin and spore-wall protein of Bacillus sphaericus C3-41 were extracted respectively from spore-crystal complex. When subjected to SDS-PAGE, spore-crystal toxin might give two toxic protein bands (43 and 40 kilodaltons), but spore-wall protein had only a protein band (MW 104 kD), which was degraded into toxic 43 and 40 kD proteins by using NaOH. The LC50 values of spore-wall protein and spore-crystal toxin purified by Sephadex G-75 were 267 and 10 ng/ml respectively against the third instar larvae of Culex quinquefasciatus at 48 hours. The results of immunodiffusion showed that sodium hydroxide-solubilized spore-crystal toxins from spore-crystal complex of strain 2362, 1593, Bs-10 (H5a5b) and 2297 (H25) revealed cross reactions with 43 and 40 kD antiserum of strain C3-41, but those of strain K (H1), SS II-1, 1404 (H2) and 2315. (H26) without cross reaction with the same antiserum.

Mobile and immobile calcium buffers in bovine adrenal chromaffin cells

1. The calcium binding capacity (kappa S) of bovine chromaffin cells preloaded with fura-2 was measured during nystatin-perforated-patch recordings. 2. Subsequently, the perforated patch was ruptured to obtain a whole-cell recording situation, and the time course of kappa S was monitored during periods of up to one hour. 3. No rapid change (within 10-20 s) of kappa S was observed upon transition to whole-cell recording, as would be expected, if highly mobile organic anions contributed significantly to calcium buffering. However, approximately half of the cells investigated displayed a drop in kappa S within 2-5 min, indicative of the loss of soluble Ca2+ binding proteins in the range of 7-20 kDa. 4. The average Ca2+ binding capacity (differential ratio of bound calcium over free calcium) was 9 +/- 7 (mean +/- S.E.M.) for the poorly mobile component and 31 +/- 10 for the fixed component. It was concluded that a contribution of 7 from highly mobile buffer would have been detected, if present. Thus, this value can be considered as an upper bound to highly mobile Ca2+ buffer. 5. Both mobile and fixed calcium binding capacity appeared to have relatively low Ca2+ affinity, since kappa S did not change in the range of Ca2+ concentrations between 0.1 and 3 microM. 6. It was found that cellular autofluorescence and contributions to fluorescence of non-hydrolysed or compartmentalized dye contribute a serious error in estimation of kappa S. 'Balanced loading', a degree of fura-2 loading such that the calcium binding capacity of fura-2 equals cellular calcium binding capacity, minimizes these errors. Also, changes in kappa S at the transition from perforated-patch to whole-cell recording can be most faithfully recorded for similar degrees of loading in both situations. 7. Nystatin was found unable to make pores from inside of the plasma membrane of chromaffin cells. With careful preparation and storage the diluted nystatin solution maintained its high activity of membrane perforation for more than one week. 8. An equation for the effective diffusion constant for total cytoplasmic calcium, D'Ca, was derived, which takes into account fixed buffer and poorly mobile buffer as determined, as well as calcium bound to fura-2 and some highly mobile buffers.(ABSTRACT TRUNCATED AT 400 WORDS)

In vitro and in vivo disposition and metabolism of 3'-deoxy-2',3'-didehydrothymidine

The disposition and metabolic fate of 3'-deoxy-2',3'-didehydrothymidine (D4T) were evaluated both in isolated hepatocytes and in nonhuman primates. Rapid formation of thymine and beta-aminoisobutyric acid (BAIBA) occurred following incubation of hepatocytes with 10 microM [5(-3)H]D4T. Substantial levels of tritiated water were also detected. Exposure of cells to D4T in the presence of either 1 mM thymine or 10 microM benzyloxybenzyluracil, an inhibitor of dihydropyrimidine dehydrogenase, decreased intracellular BAIBA levels by approximately 89 and 63%, respectively. Concurrently, [3H]thymine levels increased two- to fivefold. These results are consistent with D4T being cleaved to thymine, which is then degraded to BAIBA. A similar metabolic disposition was observed in monkeys following administration of 25 mg of [5(-3)H]D4T per kg of body weight. BAIBA, thymine, and tritiated water were identified in plasma and urine. Approximately 50% of the administered dose was recovered in urine within 24 h, with the majority of the radioactivity representing unchanged drug. After administration intravenously or orally of 25 mg of [4(-14)C]D4T per kg of body weight to monkeys, a novel metabolite, designated X, in addition to unchanged D4T, thymine, and BAIBA, was also detected. The sum of the three metabolites and unchanged drug accounted for virtually all of the radioactivity in plasma and urine. Thymine and X exhibited kinetic profiles similar to that of D4T, with plasma elimination half-life of 2 to 3 h, whereas BAIBA levels remained constant for extended periods and declined slowly; this metabolite could be detected 24 h after intravenous drug administration. Mean oral bioavailability of D4T was high at approximately 70%. As observed in the [5(-3)H]D4T study performed in monkeys, approximately half of the administered [4(-14)C]D4T was recovered unchanged. The remainder was not recovered in urine or feces collected up to 30 days after drug administration. These data suggest that D4T metabolites are further metabolized by salvage pathways and/or converted to biological macromolecules.

Novel T cell antigen 4-1BB associates with the protein tyrosine kinase p56lck1

4-1BB is a 30-kDa inducible T cell Ag, and is expressed predominantly as a 55-kDa dimer on both CD4+ and CD8+ T lymphocytes. The cytoplasmic tail of 4-1BB contains the sequence Cys-Arg-Cys-Pro, which is similar to the sequence Cys-X-Cys-Pro, which mediates the binding of the CD4 and CD8 molecules to the protein tyrosine kinase p56lck. An anti-4-1BB mAb, 53A2, was used to determine whether 4-1BB may associate with p56lck. The 53A2 mAb specifically recognized 4-1BB on a CD8+ T cell line, CTLL-2, and coimmunoprecipitated a 56-kDa protein along with 4-1BB. Peptide mapping indicated that the 56-kDa phosphoprotein was identical to p56lck. The coimmunoprecipitation of p56lck with 4-1BB also occurred in nonlymphoid cells such as insect (Sf-21) and HeLa cells when the two recombinant proteins were coexpressed. Analysis of mutant p56lck recombinant proteins showed that two cysteine residues critical for p56lck-CD4 (or -CD8) complex formation are also required for the p56lck-4-1BB interaction. These studies establish that 4-1BB physically associates with p56lck.

[The clinicopathological research of post-operative recurrence of gall-bladder carcinoma]

This paper analyzed the clinicopathological factors relating to post-operative recurrence of gall-bladder carcinoma (GBC) in 71 cases, divided into group A (48 cases) dying within one year, and group B (23 cases) having been alive for longer than three years. Based on the "Japanese management rule of GBC surgery and GBC pathology" the indicators of clinicopathological S, n, binf, hinf, ly, V, morphological-classification, and histologic-classification showed significant difference between the 2 groups (P < 0.01). But pn, showed no significant difference between the 2 groups. In group A in gamma show 47.8%, Gn (+) 70.8%, curable operation 12.5%, this is worse results than group B (P < 0.01). Risk factors relating to early postoperative recurrence included: a. infiltrative way of gamma; b. deeply involved liver parenchyma (> 5 mm in-depth); c. cervical cancer. d. palliative resection.

Novel T cell antigen 4-1BB associates with the protein tyrosine kinase p56lck1

4-1BB is a 30-kDa inducible T cell Ag, and is expressed predominantly as a 55-kDa dimer on both CD4+ and CD8+ T lymphocytes. The cytoplasmic tail of 4-1BB contains the sequence Cys-Arg-Cys-Pro, which is similar to the sequence Cys-X-Cys-Pro, which mediates the binding of the CD4 and CD8 molecules to the protein tyrosine kinase p56lck. An anti-4-1BB mAb, 53A2, was used to determine whether 4-1BB may associate with p56lck. The 53A2 mAb specifically recognized 4-1BB on a CD8+ T cell line, CTLL-2, and coimmunoprecipitated a 56-kDa protein along with 4-1BB. Peptide mapping indicated that the 56-kDa phosphoprotein was identical to p56lck. The coimmunoprecipitation of p56lck with 4-1BB also occurred in nonlymphoid cells such as insect (Sf-21) and HeLa cells when the two recombinant proteins were coexpressed. Analysis of mutant p56lck recombinant proteins showed that two cysteine residues critical for p56lck-CD4 (or -CD8) complex formation are also required for the p56lck-4-1BB interaction. These studies establish that 4-1BB physically associates with p56lck.