In vivo evaluation of a new sealant material on a rat lung air leak model

The ability of an albumin-based hydrogel sealant (ABHS) to prevent air leakage through the suture line after pulmonary surgery was evaluated by comparison with that of a fibrin glue (FG). As an air-leak model, a rat lung was used in which a standard incision was made and the burst pressure for ABHS and FG was measured. The average burst pressures at time 0 for the FG and ABHS groups were 30.8+/-15.2 and 77.5 +/-19.1 mmHg, respectively. At Day 3, the value of ABHS (76.3 +/- 15.8 mmHg) was still significantly higher (P<0.05) than that of FG (60.0 +/- 21.9 mmHg). At Day 7, no statistical difference was observed between the FG group(71.2 +/- 18.6 mmHg) and the ABHS group(88.8 +/- 11.7 mmHg). Histological examination of the incision at Day 14 revealed that neither sealant was not visible at the incision site, and there was no evidence of adverse tissue reaction. It was concluded that ABHS had good sealing properties and is an alternative to FG for air leakage treatment in pulmonary surgery.

A feasible method for expansion of peripheral blood lymphocytes by culture with immobilized anti-CD3 monoclonal antibody and interleukin-2 for use in adoptive immunotherapy of cancer patients

Cultivation of T lymphocytes with immobilized anti-CD3 monoclonal antibody and human recombinant interleukin-2 induced a rapid proliferative response. This procedure was applied to expansion culture of peripheral blood lymphocytes obtained from cancer patients for use in adoptive immunotherapy. Peripheral blood mononuclear cells were separated from 20 ml of blood and cultured in anti-CD3 coated flasks with rIL-2 for 6 days, then transferred to a gas-permeable culture bag and culture continued for an additional 8 days with an increasing volume of medium. Cell numbers increased about 2000-fold during this 2-week culture. The final population contained about 30% CD4+ and 60% CD8+ cells, and all were CD3+ & HLA-DR+. NK cells comprised less than 5%. In clinical trials involving 12 cases receiving 35 infusions, the mean number of harvested T cells after 14 days culture was 3.5 x 10(10) (R = 1.6-6.8 x 10(10)), and the mean expansion index was 1560-fold (R = 409-4091). This method could be of benefit not only in immunotherapy but also for obtaining somatic cells from a small volume of blood for use in molecular or genetic analysis instead of having to perform EB virus transformation of B cells.

Latent cytomegalovirus infection enhances anti-tumour cytotoxicity through accumulation of NKG2C+ NK cells in healthy humans

Cytomegalovirus (CMV) infection markedly expands NKG2C+/NKG2A- NK cells, which are potent killers of infected cells expressing human leucocyte antigen (HLA)-E. As HLA-E is also over-expressed in several haematological malignancies and CMV has been linked to a reduced risk of leukaemic relapse, we determined the impact of latent CMV infection on NK cell cytotoxicity against four tumour target cell lines with varying levels of HLA-E expression. NK cell cytotoxicity against K562 (leukaemia origin) and U266 (multiple myeloma origin) target cells was strikingly greater in healthy CMV-seropositive donors than seronegative donors and was associated strongly with target cell HLA-E and NK cell NKG2C expression. NK cell cytotoxicity against HLA-E transfected lymphoma target cells (221.AEH) was ∼threefold higher with CMV, while NK cell cytotoxicity against non-transfected 721.221 cells was identical between the CMV groups. NK cell degranulation (CD107a(+) ) and interferon (IFN)-γ production to 221.AEH cells was localized almost exclusively to the NKG2C subset, and antibody blocking of NKG2C completely eliminated the effect of CMV on NK cell cytotoxicity against 221.AEH cells. Moreover, 221.AEH feeder cells and interleukin (IL)-15 were found to expand NKG2C(+) /NKG2A(-) NK cells preferentially from CMV-seronegative donors and increase NK cell cytotoxicity against HLA-E(+) tumour cell lines. We conclude that latent CMV infection enhances NK cell cytotoxicity through accumulation of NKG2C(+) NK cells, which may be beneficial in preventing the initiation and progression of haematological malignancies characterized by high HLA-E expression.

The essential light chains constitute part of the active site of smooth muscle myosin

Myosin, a major contractile protein, characteristically possesses a long coiled-coil alpha-helical tail and two heads. Each head contains both an actin binding site and an ATPase site and is formed from the NH2-terminal half of one of the two heavy chains (relative molecular mass, Mr, 200,000) and a pair of light chains; the so-called regulatory and essential light chains of approximately Mr 20,000 each. Recently we have identified Trp 130 of the myosin heavy chain from rabbit skeletal muscle as an active-site amino-acid residue after labelling with a new photoaffinity analogue of ADP, N-(4-azido-2-nitrophenyl)-2-aminoethyl diphosphate (NANDP). Nonspecific labelling was eliminated by first trapping NANDP at the active site with thiol crosslinking agents. Exclusive labelling of the heavy chains with no labelling of the light chains agreed with previous findings that the heavy chains alone contain the actin-activated Mg-ATPase activity of rabbit skeletal myosin. Here we report similar photolabelling experiments with smooth muscle myosin (chicken gizzard) in which 3H-NANDP is trapped at the active site with vanadate and which show that both the heavy chains and the essential light chains are labelled. The results indicate that both chains contribute to the ATP binding site and represent the first direct evidence for participation of the essential light chains in the active site of any type of myosin.

Carinal reconstruction with a Y-shaped collagen-conjugated prosthesis

BACKGROUND

Carinal reconstruction by direct suturing is associated with a high mortality because high tension at the anastomosis can lead to tracheobronchial fistula. A new tracheal prosthesis was therefore designed for reconstruction of the tracheal bifurcation and applied for experimental carinal replacement in dogs.

METHODS

The main frame of the new prosthesis consists of a Y-shaped Marlex mesh tube (C.R. Bard, Inc, Billerica, Mass) reinforced with polypropylene spirals, to which collagen extracted from porcine skin is chemically conjugated to provide biocompatibility and airtightness. This conjugated collagen is composed of amorphous and sponge collagen layers. The tracheobronchial bifurcation was replaced with the prosthesis in 10 beagle dogs.

RESULTS

Eight dogs survived the postoperative period, and 2 dogs died within 4 days after the operation. Bronchoscopic examination revealed that the tracheal prosthesis was covered with smooth whitish tissue and that no stenosis or dehiscence was present in the 8 dogs even 6 months after the operation. Slight mesh exposure was recognized in 1 dog. Histologic examination revealed that approximately one half of the luminal surface was covered with ciliated columnar epithelium or nonciliated squamous epithelium. In the remaining lumen, especially in the middle portion of the prosthesis, connective tissue without epithelium was observed.

CONCLUSIONS

These long-term results indicate that our bifurcated tracheal prosthesis can be used for reconstruction of the tracheobronchial bifurcation with long-term safety.

Type II collagen is a target antigen of clonally expanded T cells in the synovium of patients with rheumatoid arthritis

OBJECTIVE

To investigate whether type II collagen (CII) is recognised by oligoclonally expanded synovial T cells of patients with rheumatoid arthritis (RA).

METHODS

Peripheral blood mononuclear cells (PBMC) from 15 RA patients were stimulated with CII in vitro. T cell clones expanded by such stimulation were compared with the clonally expanded synovial T cells by using T cell receptor (TCR) B chain gene specific reverse transcription-polymerase chain reaction and subsequent single strand conformation polymorphism analyses.

RESULTS

Stimulation of the heterogeneous peripheral T cells with CII induced clonal expansion of T cells. In three of 15 patients, a proportion of these clones (approximately 17% to 25%) was found to be identical to expanded T cell clones in the synovium in vivo.

CONCLUSION

T cell clones that had TCR CDR3 sequences identical to those induced by purified CII were found in a proportion of RA patients. This finding suggests that CII is recognised by T cells that accumulate clonally in RA joints. Oligoclonal T cell expansion in RA joints is probably driven, at least in part, by intra-articular components such as CII.

A new type of surgical adhesive made from porcine collagen and polyglutamic acid

We have developed a new adhesive for surgical use. The new adhesive is made of three components: porcine collagen, poly(L-glutamic acid) and water-soluble carbodiimides (WSC). The optimum concentration of each component was determined by measuring the time required for gel formation in experiments in vitro. Using these optimum concentrations, we applied the adhesive to wounds made on rats. A conventional fibrin glue was used as a control. Measurement of tensile strength and histological examination were performed 5, 7, 10, and 14 days after the operation. The tensile strength of wounds treated with 2.5 mg/mL collagen glue was not significantly different from that of wounds treated with fibrin glue except at 7 days after the operation (p < 0.05 by Student's t-test). Histological examination revealed that the speed of cell infiltration into, and absorption of 2.5 mg/mL collagen glue was slower than for fibrin glue, but faster than for 5.0 mg/mL collagen glue. One of the important advantages of our collagen glue is that the absorption rate of it can be controlled by the collagen concentration. Therefore, it seems to be adequate for sealing air leakage from the lung, which takes a relatively long period for recovery. Moreover it does not contain human serum, and, hence, it requires no blood donation and can be obtained with low cost.

Mechanism of burn injury during magnetic resonance imaging (MRI)--simple loops can induce heat injury

To determine the mechanism of burn injury associated with magnetic resonance imaging (MRI), the induced current in the loops of a conductive lead was measured. Seven types of loops with effective areas within the range from 100 to 12 000 cm2 were made and then each loop was placed in the bore of a whole-body MR system at 0.5 T and MRI was carried out. During radio frequency (RF) irradiation, an induced voltage was observed in loops that were placed with their axes parallel to the linearly polarized transmitting RF field. The voltage had a sincfunction characteristic and was within the range 55-235 V at the RF pulse sequence for usual MR imaging. When the axis was vertical, negligible current was observed. A resistor inserted into the circuit of a 30 x 40 cm loop sparked and burned out. Simple loops of conductive material may result in the induction of a large and potentially hazardous voltage in the imaging system. Self-resonance of such a loop may add greatly to hazards by increasing the effective coupling to the RF transmitter. Also, impedance matching of the inserted resistor with the impedance of the loop increases the dissipated power at the resistor.

Immunosuppressant-free allotransplantation of the trachea: the antigenicity of tracheal grafts can be reduced by removing the epithelium and mixed glands from the graft by detergent treatment

OBJECTIVE

To develop a method for eliminating the epithelium and mixed glands from tracheal grafts by detergent treatment and evaluate these grafts for immunosuppressant-free allotransplantation in dogs.

METHODS

Fresh canine tracheal grafts were treated with a detergent (1% Triton X-100 t-octylphenoxypolyethoxyethanol; T-9284; Sigma Chemical Co, St Louis, Mo) at 4 degrees C for 48 hours. The grafts were then used for intrathoracic 5-ring tracheal replacement in other dogs without immunosuppressant treatment (n = 6, detergent treatment group). In the control group (n = 6) fresh untreated canine tracheal segments were implanted as allografts. All the implanted grafts were covered with an omental pedicle.

RESULTS

In the detergent treatment group the chondrocytes in the graft had a similar appearance to those in the fresh trachea, indicating that the chondrocytes remained viable after the detergent treatment. In 5 of the 6 grafts, the epithelium and mixed glands had been removed completely. After transplantation, these 5 grafts were incorporated by the host trachea without stenosis. In the remaining treated tracheal graft, in which removal of the epithelium was incomplete, moderate stenosis was observed at the fourth week after implantation, although this was not progressive. In the control group, granulation tissue of the graft and significant stenosis were observed after transplantation.

CONCLUSION

The antigenicity of tracheal grafts can be greatly reduced by removing the epithelium and mixed glands by the use of detergent treatment. The epithelium and mixed glands of the graft appear to be the determining elements involved in rejection after tracheal allotransplantation.

Use of a newly developed artificial nerve conduit to assist peripheral nerve regeneration across a long gap in dogs

There is now considerable evidence that peripheral nerves have the potential to regenerate if an appropriate microenvironment is provided. However, there are only a few reports of the successful use of artificial nerve conduits to repair major nerve defects more than 30 mm in length. In this study, we examined nerve regeneration across a long gap in the dog peroneal nerve using a novel artificial nerve conduit developed by our group. The conduit consists of a polyglycolic acid (PGA) collagen tube filled with laminin coated collagen fibers. In 12 dogs, the nerve conduit was implanted across an 80 mm gap in the left peroneal nerve. Three months after surgery, compound muscle action potentials (CMAPs) and somatosensory evoked potentials (SEPs) were detected. Evaluation of locomotor function revealed obvious limping for up to 3 months, but no marked difficulty in walking by 6 months. Microscopic observation of the regenerated nerve segment at 12 months showed numerous myelinated nerve fibers, which were smaller in diameter and enclosed in a thinner myelin sheath than normal axons. These results suggest that our artificial nerve conduit has potential usefulness in enhancing peripheral nerve regeneration, even across large gaps.

Intrasarcomere [Ca2+] gradients and their spatio-temporal relation to Ca2+ sparks in rat cardiomyocytes

1. Line-scan analyses of spontaneous Ca2+ sparks, non-propagating local rises in Ca2+ concentration, and the early phase of Ca2+ transients in cardiomyocytes were performed with a rapid-scanning laser confocal microscope (Nikon RCM8000) and fluo-3. 2. On electrical stimulation, points at which rise in Ca2+ began earliest were observed at regular spacings of 1.82 +/- 0.26 micron (mean +/- S.D.) along the longitudinal axis of the cell. The points were heavily stained with di-2-ANEPEQ, which stains the T-tubules, indicating that they were at the Z-line. 3. The points where spontaneous Ca2+ sparks originated coincided with the points which showed faster Ca2+ elevation, i.e. the Z-line. 4. In some cases where a Ca2+ spark had occurred within about 30 ms before the evoked Ca2+ transient, fast elevation of Ca2+ was not observed at the corresponding Z-line, indicating the presence of a refractory period in Ca2+ release from the SR. 5. The present results provide visual evidence for Ca2+ release from the junctional sarcoplasmic reticulum in cardiomyocytes. The presence of a refractory period in Ca2+ release after Ca2+ sparks provided new evidence that the normal Ca2+ transient may be the summation of Ca2+ sparks.

Interaction of alkali light chain 1 with actin: effect of ionic strength on the cross-linking of alkali light chain 1 with actin

To determine the spatial relationship between alkali light chain and actin in the actosubfragment-1 complex, we studied the cross-linking of actin and subfragment-1 with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide. We found that (a) alkali light chain 1 was cross-linked to actin at two sites in the extrapeptide region, and (b) cross-linking of these two sites, especially the one which was very close to the NH2 terminal of the alkali light chain, to actin was inhibited drastically when the KCl concentration was increased from 0 to 100 mM. Since the inhibition of cross-linking with carbodiimide reagent means separation of amino and carboxyl groups in alkali light chain and actin, we suggest that this decrease in electrostatic attraction is the reason why subfragment-1 with alkali light chain 1 has higher affinity to actin than subfragment-1 with alkali light chain 2 at low ionic strength but has almost the same affinity at moderate ionic strength.

Regulation of differentiation and proliferation of rat hepatocytes by lactose-carrying polystyrene

We noticed that hepatocytes recognize the structure of oligosaccharides via asialoglycoprotein receptors and synthesized lactose-carrying styrene polymer (PVLA) as an asialoglycoprotein model. We found that the regulation of differentiated function and proliferation of hepatocytes that were cultured on polystyrene dishes can be achieved by varying the amount of PVLA coated on the dishes. The 3H-thymidine uptake of cultured hepatocytes is low for cells cultured on dishes coated with high amounts of PVLA in which the hepatocytes are round and is highest for those cultured on dishes with a low PVLA coating level in which the hepatocytes are spread in shape. Moreover, bile acid release as a typical differentiated function of hepatocytes was maintained at higher levels in hepatocytes attached on dishes coated with a high level of PVLA. Our results indicated that regulation of differentiated function and proliferation in hepatocytes could be achieved by specific ligand-mediated recognition of microscopic surface structure. Thus, it may be possible to regulate proliferation and differentiation of hepatocytes by design of the culturing substrata.

Diagnostic and clinical importance of interleukin-2 receptor alpha chain expression on non-T-cell acute leukaemia cells

The expression of interleukin-2 receptors (IL-2R) was examined in 328 adult patients with non-T-cell (non-T) acute leukaemia and blast crisis of chronic myelocytic leukaemia (CML.BC) using two monoclonal antibodies, anti-Tac for IL-2R alpha chain (IL-2R alpha) and Mik beta 1 for IL-2R beta chain (IL-2R beta). Leukaemic cells in the following cases were positive for anti-Tac; 28/192 of acute myelocytic leukaemia (AML), 24/44 CML-BC, 4/28 CD19(+)CD10(-) acute lymphoblastic leukaemia (ALL), and 20/64 common ALL (c-ALL). IL-2R beta was not detected on leukaemic cells of any case examined. Eleven of IL-2R alpha(+) AML were derived from myelodysplastic syndrome. None of the IL-2R alpha positive leukaemic cells responded to exogenous recombinant human IL-2 (rhIL-2) in culture. In addition, IL-2R alpha expression on non-T leukaemic cells was closely correlated with coexpressing different lineage markers and the presence of the Philadelphia abnormality. Marked increase of serum soluble IL-2R alpha was demonstrated in the IL-2R alpha(+) patients examined. Clinically, the IL-2R alpha(+) patients showed significantly lower response to chemotherapy and poorer prognosis than IL-2R alpha(-) patients. Our results clearly indicate the diagnostic importance of IL-2R alpha expression in non-T acute leukaemia with a close relation to the particular cellular characteristics and the prognosis.

Interaction of myosin subfragment-1 with actin. II. Location of the actin binding site in a fragment of subfragment-1 heavy chain

The heavy chain of subfragment-1 prepared by chymotrypsin treatment had a molecular weight of about 96K. The heavy chain was split into 26 K, 50 K, and 21 K fragments by trypsin. When the trypsin-treated subfragment-1 was cross-linked with dimethyl suberimidate, cross-linked products of 26 K, 50 K, and 21 K fragments and of 50 K and 21 K fragments appeared, but there was little cross-linked product of 26 K and 50 K fragments or of 26 K and 21 K fragments. When the cross-linking experiments were carried out in the presence of actin, a new band appeared and the amount of cross-linked product of 26 K, 50 K, and 21 K fragments decreased by about 50%. The molecular weight of the new band was lower than that of the cross-linked product of 26 K, 50 K, and 21 K fragments, and higher than that of the dimer of actin. Based on this and some other results, we suggest that this band represented a cross-linked product of actin and the 50 K fragment. We also suggest that the decrease in the amount of cross-linked product of 26 K, 50 K, and 21 K fragments reflected the conformational change in subfragment-1 due to the binding of actin.

Mechanical properties of artificial tracheas composed of a mesh cylinder and a spiral stent

Much work has been done on the materials used for mesh-type artificial tracheas, but a precise mechanical evaluation of these structures has not yet been performed. In the present study, we determined the mechanical properties of typical mesh-type artificial tracheas and compared them with those of native trachea. Four types of artificial trachea were made and used for the mechanical tests. The basic frame of all the specimens was composed of a mesh cylinder and a spiral stent. The specimen whose mesh was sealed with collagen sponge showed almost the same behavior in the force-strain curve under compression, suggesting that collagen sealing has little effect on mechanical properties. Agreement between measured and estimated mechanical properties was good, especially in the low strain region, suggesting that artificial tracheas can be designed in terms of mechanical properties by mainly considering the basic frame structure.

Cloning, functional characterization, and localization of a rat renal Na+-dicarboxylate transporter

We report here the isolation, functional characterization, tissue distribution, and membrane localization of rat renal Na+-dicarboxylate transporter (rNaDC-1). rNaDC-1 consists of 2,245 nucleotides, and the deduced amino acid sequence showed 73% and 75% identity to rabbit and human NaDC-1, respectively. When expressed in Xenopus laevis oocytes, rNaDC-1 mediated sodium-dependent uptake of di- and tricarboxylates. Substrates of rNaDC-1 evoked inward currents in oocytes expressed with rNaDC-1; succinate, alpha-ketoglutarate, and glutarate were relatively high-affinity substrates, and citrate was a low-affinity substrate of rNaDC-1. The coupling ratio of citrate to charge was determined to be 1:1 at pH 7.4; influx of one positive charge per citrate molecule suggests a symport of three Na+ with a divalent citrate. Expression of rNaDC-1 mRNA was detected in the kidney and the small and large intestines. Immunohistochemistry using polyclonal antibodies raised against the 14 amino acids at the COOH terminus of rNaDC-1 revealed that rNaDC-1 is localized exclusively in the luminal membrane of S2 and S3.

Two-dimensional millisecond analysis of intracellular Ca2+ sparks in cardiac myocytes by rapid scanning confocal microscopy: increase in amplitude by isoproterenol

Two dimensional images of myocardial Ca2+ sparks, non-propagating local rises in cytoplasmic Ca2+ concentration, were obtained at 4 msec intervals with a rapid-scanning confocal laser microscope, Nikon RCM 8000, and fluo-3. Spontaneous Ca2+ sparks were observed at apparently random sites throughout the cytoplasm of rat ventricular cells. The duration of sparks was 30 to 40 msec and the time to peak intensity about 10 msec. Ryanodine (1 microM) completely inhibited Ca2+ sparks while nicardipine (3 microM) had no effect. Isoproterenol (1 microM) had no effect on the frequency and distribution of Ca2+ sparks but significantly increased their amplitude. These results suggest that myocardial Ca2+ sparks are the result of spontaneous release of Ca2+ from the sarcoplasmic reticulum and that beta-adrenergic stimulation may result in functional modification of the ryanodine receptor channel.

Distribution and therapeutic effect of intraarterially transferred tumor-infiltrating lymphocytes in hepatic malignancies. A preliminary report

Indium-111-labeled tumor-infiltrating lymphocytes (111In-TIL) were transferred as an intrahepatic arterial bolus to determine their in vivo distribution in patients with hepatic malignancies. In the in vitro culture system, TIL were expanded upon simultaneous stimulation by recombinant interleukin-2 (rIL-2) and immobilized anti-CD3 monoclonal antibody. This double activation led not only to a larger cell yield, but also to a significantly more dominant subpopulation with CD4+ phenotype than occurred with activation by rIL-2 alone. Accumulations of 111In-TIL in the liver were identified by scintigraphy in all of three patients, corresponding to the tumor localization by computed tomography. Such accumulation had persisted for at least 48 hours after infusion. After intraarterial chemoimmunotherapy that included TIL, two of three patients achieved a partial therapeutic response. The authors conclude that their method of culture and transfer can facilitate the accumulation of TIL at tumor sites, which may augment the antitumor effects of adoptive immunotherapy.

Role of sarcoplasmic reticulum in myocardial contraction of neonatal and adult mice

Changes in action potential parameters by and inotropic responses to nicardipine, verapamil, ryanodine and cyclopiazonic acid were examined in isolated ventricular myocardial preparations from neonatal and adult mice. The action potential of both neonatal and adult mice had a unique configuration with little evidence of a plateau at depolarized membrane potential; the action potential duration was significantly larger in neonatal preparations. Nicardipine had no effect on action potential parameters in the adult while it significantly shortened the action potential duration at 50% repolarization in the neonate. Ryanodine significantly shortened the action potential duration at 80% repolarization at both ages: the shortening was significantly larger in the adult when compared with the neonate. The contraction of ventricular preparations from adult mice were relatively resistant to nicardipine and verapamil. Nicardipine or verapamil, even at 10(-5) M, only decreased the contractile force to 70% of control values; the decrease was much less than that reported in other experimental species such as chick, guinea pig or rabbit. In the neonate, 10(-5) M nicardipine or verapamil decreased the contractile force to 30% of control values. Ryanodine had a potent negative inotropic effect both in the neonate and adult; the effect was significantly larger in the adult. Cyclopiazonic acid produced a decrease in contractile force and prolongation of the time required for relaxation; both effects were significantly larger in the adult. These results suggest that the contraction of the adult mouse myocardium is highly dependent on SR function and less dependent on transsarcolemmal Ca2+ influx when compared with the myocardium of the neonatal mouse and that of other species.